evolution works on populations, not individuals. There are examples of species with a high proportion of nonreproducing individuals. You can't simple deduce the correct answer to questions like this.
In fairness RKS only ventured a hypothetical, and it was at least an interesting one. There would be a bizarre irony in the freedom to come out being bad for the homosexuality genes. Though I agree with you that I suspect it won't work like that. In evidence I cite that homosexuality hasn't died out in past human societies where it was openly practiced AFAIK.
Canis Lupus, just as a mammalian example. There is an extreme example in the social insects. (Order Hymenoptera?) I didn't mean it to be serious proposition, just a conceit. I suspect the premise is flawed, that a gene or group of genes is responsible for inflexible, lifelong preference for one's same sex is unlikely. Probably it is just a "wild type" being acted on by unusual environmental factors. Even if were true, there is no reason to suppose that it would have an appreciable effect on gene frequency, necessarily. Then there is the question of why some societies, like The Greeks and Romans, didn't make the same rigid distinctions we do. It was useful in their societies to redirect the sexual drives of males, in certain circumstances, to boys, and then back to females for procreation. Some say that they had no heterosexuals and homosexuals, but I would argue that that pattern in society masked those who were different in the sense that they primarily responded to visual stimuli from same sex secondary sexual characteristics. My objection to public policy that allows same sex marriage is that it furthers the view that sex is primarily for pleasure rather than procreation. The declining birth rates of advanced Western societies should be of concern to us. (The Death of The West) Earlier Western societies did a better job of integrating homosexuality into their cultures than we do, to wit, the Castrati. Even though it was strictly banned by the Church, it was accepted as a part of high culture with a wink and a nod by the elite.