Uhm...species don't set out trying to improve their genetic diversity. That sort of just happens through mutation and population increase.<quoted text>
Plumage is a survival strategy, it is how the species improves it's genetic diversity. You speak from ignorance, that is easy to see, but you should actually look up and study something before making assertions. There are also many instances of homosexuality in many animals, we are not unique in that regard. That is what bothers you most, I am betting, having to admit that we are indeed animals.
Everything else you wrote is spot on though.