Not necessarily.
Consider matrilocal societies, where the man goes to live with his wife's clan. Heterosexual boys do not contribute to their clan, because they will leave when it's time to get their own wives. Homosexual boys will tend to stay with the clan, and contribute to the survival of the clan, including the children of their sisters, who share much of their genes.
Matrilocal societies were pretty much superseded by patriarchal societies, where the woman would go live with her husband. At that point, the gay gene became much less useful.
From my experience with homosexuals, they are very little interested in protecting the tribe, but very interested in passing on their diseases through the tribe. And at least half of them are useless as tits on a boar with anything stressful.
Besides genes are designed, not designers.
Would not a tribe be strengthened by the addition of a new male setting up a family to support vs an old male looking to cohabitate with another old male. Have you met homosexuals that are more interested in society’s needs than their own? I have not, not one, not yet.
Truly a dead end, homosexuality.