And where do you think racism stems from?  You think people being against blacks marrying whites was based on anything other than people interpenetrating books like The Bible in a way that coincided with their own personal beliefs?

Just because something is a "long-held religious belief", that does not all of a sudden give you an excuse to discriminate against someone when you are running a business that serves the public.  If you want to discriminate and only cater to people who you agree with, then you should do your work freelance - in which case, I couldnt care less what your personal beliefs/policys are.