Can you elaborate on the "most of humanity" part? One example of negative look on incest I know of is that one guy in bible that did wrong everything that can be done wrong, and ended up drunkraped by his two daughters, giving start to the two hostile tribes. Almost as if the makers of bible wanted to say "hey suckers, your grandad was a loser and you are all descendants of fatherfuckers". Pretty childish for such a famous work, but makes for effective propaganda I guess.

Strange how you are so sure about what humanity thinks while disagreeing with it, almost like you aren't the part of humanity.