Sexual "deviance" is punished more among traditional cultures because it threatens the strength of the group. They need heteronormative relationships to keep population up, and people who don't participate may even be seen as not contributing to the group (we see this when single men or women are accused of selfishness for not wanting to have children).
It's no surprise that groups of ethno-purists would also latch onto this behavior to keep their bloodlines "clean."
Sebastian Junger explores much of the nuance of traditional cultures in his book Tribe, which is an approachable and quick read (and a nice listen on audiobook).
We get a lot of masculinity perspectives on these behaviors at the moment, but I appreciate the way you've approached the subject.