The celebrations are disproportionate because when the past n hundred years have been spent in an atmosphere where you're regarded as an aberration at best and something to be beaten up or killed at worst, you're going to be chuffed when the law says you can do the same things (that harm no-one) that straight people can do.
Having negative feelings about homosexuality is, quite frankly, a ridiculous state of mind. It's like getting all up in my business because I don't like tinned salmon.
To wit: as long as The Gays are not forcing you to either participate or watch (goes for straights, too; kiss/grope/fuck your partners in private, please), butt the fuck out. It's got nothing to do with you.
I know I'm super-liberal about this sort of thing, though. As long as it's safe, legal and doesn't frighten the horses, I don't care who does what to whom with what. If two (or more!) people want to commit to each other, and codify that in a legal sense, good for them.