Here's our first look at a really rude customer. Only when someone has experienced really bad service should a tip be withheld. When that happens, it would be helpful if the customer provided some feedback, so the restaurant knows where it went wrong.
This is not helpful feedback. This is just patronizing, and doesn't help anybody. The restaurant hasn't failed anyone here - the customer has failed the test of basic politeness and decency. They should boo themselves.