So if churches should be allowed refuse to marry homosexuals couples, should they be allowed to refuse to marry mixed race couples if it goes against their doctrine?
You say that as if you think, "Ah hah, but RACE!" is some sort of universal trump card to play, a boundary over which nothing can EVER be allowed to cross and the defense of which is sacrosanct.
Let me advance what is probably a radical notion to you. It is completely legal for someone to be an asshole, and even a racist asshole, and while it is repugnant and immoral behavior for one to be such, it is far more repugnant and immoral for someone to try to impose by law their own preferred behaviors onto said racist asshole.
I would rather live in a society where people have the freedom to be ignorant bigots than one where everyone is a well-behaved slave.