Angry Owner Kicks Christians Out of His Coffee Shop

I sympathize with the owner's anger. He saw that group (correctly, I expect) as being representative of the people who have been fomenting hatred against him (and all gay people) all his life.  In his shoes, I might have reacted the same way.

That said, if those Christians wanted to follow up with a formal legal complaint, the law would be (and should be) on their side (simple religious discrimination).