I think the problem here is that people are under the impression that homosexuality is illegal, and it isn’t. There isn’t anything stopping gay people from marrying at a church that supports their union, so technically, it’s already possible for churches to perform gay marriage legally.
I don’t think the government should be doing anything, at all, under any circumstances. I don’t think pacifying people with a “right” that shouldn’t even exist for straight couples is conducive to them asking the question of why government is involved in personal relationships in the first place. The reason the government won’t become smaller or go away completely is due to the fact that no one questions it, and even the people that do think that “baby steps” can be made in taking away institutions that aren’t essential to our survival because they’re too scared to make the statement that it should all stop and it should all stop now. I don’t think bringing down the government tomorrow in its entirety would be a good thing, but I do think that there are certain areas of the government that we could bring down tomorrow and it wouldn’t send society into chaos, and getting rid of state involvement in marriage is one of them.
The state institution of marriage started out as bigoted (banning interracial marriage), and it has continued to be so, both legally and/or socially. I don’t think the solution will ever be to include everyone in something that was clearly set in place to control people from the very beginning.