Shut the restaurant down, throw him in jail.
A little extreme? I mean, aside from a few very offended people, what harm has he caused (financial, reputational or physical)?
What harm does discrimination ever cause to anyone?
Hurt feelings. If that was a crime, we'd all be in jail.
Now, while I do agree that this guy seems like an utter and absolute joke, the statement you made on it's actual grounds seems to really understate the effects of discrimination. We had a Civil Rights movement for a reason, after all. Discrimination has had a damning effect on this nation, on both non-white and white people. I'm sure if your Catholic cousins were alive in 1892, they certainly wouldn't feel welcomed by the general society of the time that would view them as papist criminal scum.