It isn't all about your personal genes, the gene pool counts too.

There is probably an evolutionary advantage to a population having some non-reproducing members, particularly in a species where the strategy is to keep individuals alive rather than out-breed the environment. Probably not a lot of gay bunnies.

I interpret the correlation you observe differently. If you are constantly being told that a certain type of person is bad, and you believe it, and you come to realize that you are one of those, that can't be good for your mental health. Of the people I've been around, some of the most mean and dangerous were both openly gay and very homophobic. Really bad combination. Self-loathing is quite toxic. I suspect closeted gay and homophobic is even more so, but my experience does not include any people who came out of the closet after I got to know them, so I don't know.