I don't know if there's any modern equivalent of ancient Mesopotamian sacred temple prostitution or the public fertility rituals of Inana to compare with.
https://www.arthistoryproject.com/t...he-fertility-ritual-of-inana-and-iddin-dagan/
But what we're looking for isn't evidence of public sex and depictions of sex in ancient civilizations (which is plentiful), it's evidence that any of it was considered harmful to children, to be consistent with your claim regarding "the majority of humanity since forever." Such as, a few words in writings like the above to mention children being barred or sequestered, or a legal penalty for failing to do so. You haven't shown me any, and I haven't found any when I've stepped up to do your work for you and looked myself.
You have provided not a shred of evidence for your claim so far. Ironically I've found a small amount of evidence myself (regarding a few brief periods of second-millennium Chinese history; and of course, China is going through another such period in the present day as its government champions all forms of censorship and repression including a porn ban), but it appears to be rare exceptions rather than "the majority."