No one is going to force the Christians to change their values. You have to remember the 1st amendment is there to protect all religious ideals even the ones that are not so popular. As long as those ideals do not harm anyone I see no reason why a Christian majority should be able to ban these people's 1st amendment right to practice their own religion. There are religions that allow gays to marry so why are their religious freedoms not protected?
If I had it my way the government would be out of the marriage business but as it is now it's the Christians that are imposing their will on the other religions by using the government to define what a marriage is.
I don't want to tell you how to worship your god. I just have a problem when people use government to tell me how to worship mine.