What's wrong with being gay? I'll tell you what's wrong with it. It isn't 'normal' and is in the minority when you compare the amount of gay couples, and straight couples. And basically, if it's not the majority, people tend to react negatively to it. If, somehow, gays were in the majority, I believe straight would have a negative connotation with it.
That being said, I'm all for gay people. But I suppose the same could be said about gay people as about race. "I don't see color, just people." Is equal to (nowadays) "I don't see gays, just people."