In the sphere of thought, absurdity and perversity remain the masters of the world, and their dominion is suspended only for brief periods.
-Arthur Schopenhauer
About the worst and most fruitless idea humanity ever had is the idea of the gods. Of course, religion has convinced most people that the gods were one of the best ideas humans ever had.
Monotheism has this way of reversing values. Nietzsche wrote about it. Whatever the world finds good, religion will eventually demean. Whatever the world reviles, religion finds a way to redeem. Shall we look at some examples together?
Death. What could be of less importance to us than what happens after we die? Predictably, the churches insist that the most important consideration in life is what happens after we die.
The Individual. Religion does not recognize your right to privacy, or your right to yourself, to "autonomy". Religion has its source of glory and power in death, not in life -- in the fear of death, in mummery about death, in fake wisdom about death, in fake knowledge about death. Religion and death are inseparable. Your death is not something religion fears, in fact, it is something religion can quickly use to glorify itself.
Orgasms. The world finds them to be pleasant and very good. Religion does not care about pleasure, and deems orgasms bad, insignificant, maybe even subhuman.
Erections. All men know they feel good. Some folks find them attractive. Religion reviles erections, and men all over the world feel guilty about this natural source of pleasure and pride. Those who find them attractive are ashamed of their taste.
Sex. The most satisfying part of life has to be crimped and clipped and hushed and pushed way to the back of every mind so far as the church is concerned. What life teaches is its foundation, and which it shows us is life's greatest pleasure, the very wine of wines, has to be reviled and restricted to a narrow, moralistic baby-maker's schedule by the tyrannical church. Everything sexual that does not aim at procreation is reviled.
Women. Over half of humanity is female, and that is good. The female differs from the male, and that is also good. But the church does not see things that way. Women are harder to control than men, and that too is good. But the church disagrees with the world at large on this too. Women must be demeaned, stopped, stunted, hushed and neglected so far as religion is concerned with them at all.
Love. Something that comes in myriad forms and fills hearts in thousands of different ways is reduced by the church to a narrow path from hello to marriage. Anything that veers from the path is slandered and reviled. Brief affairs, friends with benefits, paramours, lovers, serious but never going to marry, trying it out for a while -- such relationships are of no interest to the church. Every encounter of the heart is either trash or a step on the ladder to marriage. Nothing else can be recognized or discussed.
Church/Worship. There is almost nothing in ordinary daily life that is worse than sitting in church. In fact, almost everything you can think of is better than church. Cleaning the garage is better than church. So is a root canal. At least they are not boring or preachy. But of course, the church holds that there is nothing better or more important than church, and they want to make that evaluation imperative. To that end they condemn everything that competes with church. Sport, money, fame, lawn care, career, profession, self-discovery, jogging, biking, sleeping late -- you name it. If it competes with church for attention or pocket change, the church throws shade on it.
The State. Religion does not recognize the authority of the state, and thinks instead that the state has to come to religion for legitimacy. Religion recognizes no authority other than itself, and when it is strong enough it will supplant the state.
For most of history, other cults are tolerated and interpreted favorably by the priests of a home cult. For example, if we have a temple of a goddess of fertility, and a temple for a sea god is built nearby, the priesthood of the goddess will for the most part look favorably on the sea god and his cult, and the new sea god ministry will look favorably on the goddess cult and its ministers. This is the normal way things go. A cult is strengthened by the existence of other cults.
Occasionally, however, a cult arises that looks unfavorably on another cult, or on several of them, or on all of them. Wherever a cult arises that looks at all other cults unfavorably, a nascent monotheism is afoot. It should be nipped in the bud immediately. It is a mistake for the other cults to allow this one cult to thrive because its reason for existence is to discard other gods and to appropriate the authority and glamor of their cults. The priesthood of a monotheism is a mortal threat to the priesthoods of all other cults. They should always be eliminated, but in Rome, fascination with danger was endemic, and nascent monotheisms grew. Sol Invictus, Mithras, Jesus -- all of them were mortal threats not only to the cults of Jupiter and Minerva, but also to the authority of the state.
Science. The greatest cultural achievement of mankind is the greatest threat to the priest's power. So, of course, the church hates and reviles science. One way they attack science is to lie about its foundations. Christian apologists like to claim that science could only get going because of religion. But religion is falsehoods all the way through, and a crucial part of science is simply the rooting out and rejection of falsehood. There is no way that something as false and partial and narrow as religion could be the foundation for something far broader, truer and more impartial. Religion as a foundation of science is like lies as a foundation of honesty, or murder as a foundation of love. It just ain't so. Religion came into the world long after learning was fully established.
Entertainment/culture/art. People spend an inordinate amount of time with the arts these days. In the past, one did not see drama or hear music unless it was done live. A hundred years into the era of recorded sound, people commonly spend the bulk of their free time with TV drama, movies, music, writing and images. The more the burden of work has been reduced, the more entertainment with art has increased to the point now that some people feel incomplete without music or visuals. Art is good sayeth the people. What say the churches? Art that does not promote our world view is bad. Art that does not moralize as we wish is bad. Of course they have to hate the freedom of art. Like science, independent art is a huge threat to the power of priests.
Self-delusion. Much ink and wood pulp have been devoted to the topic of self-deception since the enlightenment. It is one of the greatest enemies of progress and a complete stop to self-improvement. But despite this, the churches insist on faith, that is, on belief without reasons, a form of self-deception, as the measure of a soul and the very foundation of moral goodness.
The Hero. Jesus' main claim to fame is his lineage, and his entire life is devoted to what his father wants, unto the point of dying as a human sacrifice because his daddy wants him to. There is nothing heroic in failing to separate from the parent. There is nothing heroic in a man of thirty odd years who blindly does whatever his father wants. There can be nothing heroic in such an extreme degree of subordination. While the acts and sayings of Jesus are another matter, there is no denying that the raison d'etra for Jesus is to glorify daddy. All the life of Jesus can teach is obedience. It has no other lesson in it. There is nothing heroic (or moral) in that teaching.
Morality. Nature provides the powers of reasoning about which our monkey brains are sometimes a little too proud. It also provides plenty of morally significant data and feelings (such as pleasure, pain, desire, aversion, embarrassment, pride, shame, etc.). Moral teachings surely go back much further than any of the holy books or scriptures that are believed in today. The reason to accept this proposition is that humans have interests, but they also have the power to make very general, rule like statements. Thus we can expect them to make general, rule like statements that address their interests. You can also expect them to have done this throughout the ages that preceded the existence of religious texts (i.e. prior to the bronze age). Hence, morality (general moral rule making) is a natural product of human life, and far older than religion or worship of any kind.
Religion views morality much differently. They tend to treat humanity as too inferior a race to have thought up any useful moral rules on our own. Our morality must therefore have come from a superior source, something super human must be its origin.
Christians like to pretend that all of morality is perfectly condensed in a single statement. Church writers have filled many, many volumes with debates on moral rules, so we know that the churches do not officially believe that all of morality can be reduced to the imperative to love your fellows as you would have them love you. But the church is perfectly satisfied letting its sheep believe that all of morality can somehow be found in that one remark. The church is all about cultivating believers in miracles, you know. And if all of morality could in fact be captured in a few words, would that not be miraculous? So, let 'em believe, thinks the priest.
When they are forced to face moral reality, the Christian moralist resorts to divine command theory, a version of deontology. According to this view, as long as there is a divine command relevant to your conduct, you should follow that command. Where a divine command is lacking, there can be no sin/immorality because immorality just means violating a divine command, so far as these theorists are concerned.
Now, it is questionable whether there is a divine command against rape. Also against lying. Also against insider trading. Also against cloning humans. Also against AI generated deep fakes. Holy books say nothing about stem cells, intellectual property, brain surgery, computers or microplastics. Thus divine command theory seems a rather threadbare moral system on the one hand. On the other hand, there clearly are divine commands in the holy books that no one intends to follow, and which, in fact, many believers find morally wrong (i.e., immoral). A good example of this is the bible's divine command to stone to death all disobedient children. Another is the divine command to stone to death all brides who are not virgins. Another is the divine command to abort all fetuses that were conceived in adultery. Another is the divine command to completely disallow female teachers ("Suffer not a woman to teach" preaches the mean old clod known as St Paul). Another is the divine command to not marry a divorced woman (Jesus preaches that this adultery). Now if a believer finds one of these views morally repugnant, to what biblical rule are they appealing? They must be relying on their innate moral sense, not on what they are reading.
Thus, divine command theory is simply inadequate. There are not enough commands in ancient lore about the gods to govern modern life, and there are too many divine commands in that lore that are quite simply morally wrong. Divine command theory cannot explain the wrongness of a divine command, but modern approaches to morality can.
In the end, divine command theorists do not fully believe in divine command theory. They believe in something else, which they rely on to select from among the the set of all divine commands a smaller set which they treat as authoritative. This something else is their actual morality in a very important sense, and they don't get that morality from their allegedly authoritative text. There is no remark in the bible, for example, telling us to reject St Paul's lesson on women as teachers, nor a sentence advising us to reject Jesus' harsh view of divorced women. Something outside the text drives us to it.
For more thoughts on the inadequacy of biblical morality, I recommend this video.
On the foolishness of religion and of religious morality, I recommend this one with Julia Sweeney.