A business can refuse to serve him if that statement interferes in any way with the business. Making the help nervous or uncomfortable can interfere with the business.
What world do you live in?
Hmm.
Interacial couples make me uncomfortable. I refuse to serve them.
Does that work for you?
How about: Them damn Jews got some mighty strange noses. They give me the willies. You wear are Star of David into my restaurant and I'll kick you out.
Oh, I know!
My favorite button:
You can help wipe out COBOL in your lifetime!
That should get me refused service from all major companies. They all use it for their systems, right? And it MUST make a few COBOL programmers uncomfortable.
Self promotion? Nothing there on that. It merely triggers a discussion for those who wish to ask about it, and then he can express his views.