It is false that all societies have rejected homosexuality, if by that word you mean sexual conduct between two members of the same sex.
1) Tokugawa Japan, modern West and ancient Rome/Greece to varying degrees approved of or at least tolerated without persecution gay relationships. Indeed, was it Spartans who actually encouraged fellow soldiers in certain platoons to become lovers and thus bind them more closely in soldiering?
2) In old SE Asia, transexuals(a form of homosexuality? to many on this board it would be) were often the head of local religious cults(I use the word cult without the modern connotations, merely meaning a local religious sect or group that may depend on worship or honoring of a local deity or spirit.) The prevalence of transexuals has continued in modern day Asia, especially in Thailand where it seems to have come down through the ages from that older culture.
It's normalizing a condition of mental illness, more precisely, an identity crisis that's the problem.
Your examples are my examples. There is no rationalization that can fit homosexuality into the paradigms of physical existence on Earth without treating it as an illness.
There have been a number of societies which permitted homosexual activity (it's endemic amongst Muslim men) but no society has ever considered homosexuality as a lifetyle equal to heterosexuality. Men have universally been expected to marry women and sire children. In other words, homosexuality may be acceptable as a side dish, but never as the main course.
... ancient Rome/Greece to varying degrees approved of or at least tolerated without persecution gay relationships.
Homosexuality & Same-Sex "Marriage" (Ancient Roman Satirist Slams Gays)
>ancient Rome/Greece to varying degrees approved of or at
>least tolerated without persecution gay relationships
They are conquered peoples, and we don't want to emulate negative aspects of conquered peoples.