> Is it really necessary to use mental illnesses in a pejorative way to make your point ?

He's not. That is, actually, the real problem. He's not just using it as some sort of insult but explaining the specific problem.

I've run into editors like that (they even proudly boast about it on their user page, so I'm not just projecting). I've had enough run-ins with them, and people like them, that I gave up on editing.