Shouldn't ban him, that's crazy. I actually quite enjoy his lunatic ravings, mind you I don't have to work there.
It's always better to have these types of social misfits in the public domain rather than underground, for example it's good to know exactly just how odious someone's opinions are so you can avoid or argue as you see fit. eg Nazis, Pro-lifers, Kiddy Fiddlers etc, etc.
Keep 'em coming Leo.