WWJD?

What would Jesus do?  Based on what I've read in the Bible, I think Jesus would bake the cake.  Why? Because Jesus was about non-judgment, about meeting people with love and compassion exactly where they were at w.r.t. to their personal spiritual evolution.  That's my biggest beef with established religion these days.  Most religions and practitioners thereof have lost sight of this key message in Jesus's teachings.  "Judge not, lest you should be judged."

 Image Source

Bottom line, I think everyone is entitled to BELIEVE whatever they want.  But the individual's right to believe something ends where it infringes upon the rights of another.  If you choose to operate a business in the public sphere, then you should serve the public.  If you only want to serve a subset of the public then you should make this clear in your advertising, posted signs on the outside of the business --and websites-- and preferably in the name/slogan you choose for your business (e.g., "Christian (only) Baker") that you will only serve those who happen to share your personal beliefs.  Not a great way to conduct a business in my humble opinion, but to each his own.