There is nothing about a possible genetic basis (whether complex and indirect or simple and direct) for an individuals non-reproductiveness that implies it has to result in extiguishing itself.
Humans are social enough that genetics which benefit the group at the expense of the individual are perfectly selectable.
Heck it even works for utterly antisocial species.
All that's required for a trait to persist is for it to be good for any members by any means. It doesn't have to be good for the individual carrier, and it doesn't have to be good in a way that we happen to understand.
> If a gene copy confers a benefit B on another vehicle at cost C to its own vehicle, its costly action is strategically beneficial if p_B > C, where p is the probability that a copy of the gene is present in the vehicle that benefits. Actions with substantial costs therefore require significant values of p. Two kinds of factors ensure high values of p: relatedness (kinship) and recognition (green beards).
The Selfish Gene is probably the most famous way of looking at that concept. https://en.wikipedia.org/wiki/Gene-centered_view_of_evolutio...
For this analogy to be equivalent, it should lead to having gay children benefit the adults enough to allow for more successful breeding.
I do am not commenting on one's gayness has a genetic basis, because I also have not idea.
(I'm not commenting on whether being gay has a genetic basis or whether it's an example of kin selection, because honestly, I have no idea.)