As a business owner, there are clients I will not do business with because of past dealings or client reputation.  Absolutely nothing to do with racism, bigotry, or religion.  It's about my own right to choose to whom I want to do business with.  In the baker's case, consider your reaction if the baker was jewish and was asked to decorate a cake with antisemitic decorations.  Does not the jewish baker have a right to say no?