I don't know that the Republican Party formally condemns homosexuality (other than the religious right wing of the party). The difference is that the GOP does not believe that this particular lifestyle should be given special treatment in public policy, or officially declared "normative."
They love to scream discrimination, when it's really special treatment that they are demanding. And the supposed "right" to marry each other is nothing more than a grab for Social Security benefits. As Rush says, "Follow the money".