Why do the world's major religions and ancient ideologies consider carnal lust to be bad

It is a theory that developed later that human evil comes from sex and love.

This is the trajectory of the cultural development that led to the advancement of the cultural concept of what is the private life of the self, that it cannot and should not be publicized in the public sphere, and the linking of these very private matters with other concepts of wrongdoing, demonic retribution, and even the mindset of good vs. evil, which was then further consolidated and refined at many levels of life, both cultural and political. Such ideas, in turn, are propagated and practically regulated at all levels of life.

But at the beginning of the ancient world, there was no such concept of good and evil linked to sex and love.

That is to say, all religious thought, and matters of ritual, were themselves free from the question of whether sex or love was right or wrong, and much of it was the interpretation of posterity rather than the original intent of the religion itself. For example, in the ancient mythological period, there was no concept of chastity. The period before the Spring and Autumn period in ancient China was also not so much a matter of etiquette, as was ancient Europe and other ancient sub-African civilizations.

Ancient Taoists also advocated the art of rooming in to nourish the body, and didn't say there was anything wrong with lust.

The concept that lust produces sin did not exist in the ancient Greco-Roman mythological system, nor did such a theory arise in the corresponding Greek philosophy.

Ancient Indian Brahminism had the famous Love Sutra, which instructed people on how to recognize and engage in sexual love.

Ancient Christianity also did not have the concept of original sin, and later interpretations of it belonged only to betraying God's norms and accepting the temptations of the heart, rather than being thought to be related to sexual eroticism.

Buddhism, which grew out of ancient Brahmanism, believes that desire itself is not wrong, but that misinterpretation of desire and clinging to desire bring all kinds of suffering. In Buddhism, the word "love" means to covet, to hold on to, not to love as we say.