While he's pretty capable of being polite, if you say something he disagrees with and then defend yourself when he replies, you'll be met with a lot of circular logic and claims that you'd agree with him if you read theory (with the linked theory always being something so long that you'd never read the whole thing unless you started off mostly agreeing with it and there being obviously dumb things right from the outset, so no one who could recognise a basic fallacy could agree with it). When he's politely arguing for evil things using flawed logic, the politeness stops being the important part.