There are different interps on that. Point is, marriage under a Christian ceremony is a function of their belief system and being denied marriage based on their belief isn't discrimination IMO.
If that is, then so is everything else for that matter (not being allowed into a women's college if you are man, a rabbi not performing a Jewish marriage for non-Jewish couples ...), where do you draw the line on "discrimination" and being allowed to have a belief system?
If you run a business, you have the right to refuse service, this is really no different.
If Chick was not serving gay people food or not hiring workers because they are gay - I get that. But simply saying that you a part of a Christian belief system and part of that belief is not believing in Gay marriage is not discrimination.
That was my only point and this type of convo is way off the topic.