The GOP is typically the religious party. That's why they're called the "religious right." And considering their religion is Christianity and homosexuality is specifically stated as being an abomination to the Lord, I can see why they say what they do.
If you don't agree with it, fine. But its a free country and they are free to believe the way they want to believe.
And as far as gay is concerned, two chicks are hot as long as both are fem. Butch girls are nasty. Two men is sicker than a dying horse.