Nature thinks gays are necessary. The world is seriously overpopulated. If a parent dies, gay uncles and aunts can act as surrogate parents. This is especially important in times of massive disaster. If parents abandon a child or teen, gay people can step in to care for the child no one else wants.
Gays males tend to be less combative than straight ones.
They tend to play the role of peacemakers and compromise makers. Gay people tend to be more funny, artistic, creative and original than straights. This is partly because they have time to develop those skills being freed from the time constraints of caring for a family. Gay people tend to mix between all social classes. They are the antidote to stratification.