I’ve often pondered the same.
I’ve also wondered if there’s a biological reason for this.
Just as sicile cell anemia is a reaction from malaria plagued regions, the human body adapts to the environment around it.
I have a theory that once a population has reached a level where more breeding individuals become a threat for scare resources and an “internal switch” happens to produce non breeders. The more masculine homosexuals add in the defense of the tribe and the effeminate homosexuals help with the female responsibilities.
It’s just my off the wall theory why homosexal behavior pops up in every society throughout time.
I think it has more to do with human childhood development, though there could be all kinds of causes.(If it were in fact a birth defect of some kind, I doubt the current atmosphere would permit even studying that...)