NOBODY on here has even proposed an alternative hypothesis to what I have suggested as being the foundation of homophobia.
Why does 'the foundation' (if there is even
one) matter? It isn't as though it necessarily follows that homophobia
now has anything to do with the original roots (supposing that they can be so readily identified) of homophobia in Western societies. There's certainly no reason to assume that the 'roots' of it must have some kind of fundamental biological meaning, and plenty of reasons to assume otherwise. Its certainly quite clear that the main factor behind modern Western homophobia is the fact that homosexuality implicitly challenges certain deeply held cultural assumptions about gender and gender roles in our society. There is certainly nothing obviously 'biological' to that, and anyone that thinks otherwise is certainly an idiot.
Because they want to have children, mostly. Sometimes there are also accidents. I'm sure that all of this was explained to you many years ago.
Because being a grandparent is objectively enjoyable on some level because it involves spoiling children, and
that is certainly objectively enjoyable.
Mostly because you don't really want to end, and death is (no matter what religious beliefs you might or might not have) certainly some kind of end. Change is scary, as is finality. I really don't see what mortality has to do with homosexuality.
Deeply held cultural assumptions about gender and gender roles, etc.
