If I designed a plain cake I would be in violation of the law?  I don't understand.  I just don't see this as a case of discrimination.  I know what discrimination is and I just don't believe that this is it.  No one was refused service.  The making of a particular product was refused.  The customer could have been anyone.  Refusing service to someone because of their race, gender, or sexual orientation is discrimination.  Refusing to provide a particular product or service to a customer regardless of their race, gender, or sexual orientation is not discrimination.  There is no legal basis (that I'm aware of) for defining discrimination against an Event such as a wedding or a particular type of wedding.  Of course, that is what the courts are debating right now.