If you'd actually played the game you'd know that that isn't how he's introduced at all. This is late in the game after you've traveled with him for several dozen hours and realized he's one of the better characters in the game, and that has nothing to do with his sexual orientation.
Who cares if he's gay or not? You do. Not the homophobes you're implying exist.
Yeah, his orientation is used for comic relief here and there. People laughing at that don't hate gay people. They can just take a joke for what it is.