In his defense, he is actually arguing, but he’s not doing it in good faith. Usually you don’t convince the other side, but the audience, and Vaush’s ‘not giving up’ and taking advantage of the good will of others is probably why he appears persuasive to many people that don’t know any better. If someone else actually grilled him and wouldn’t let him swerve away, he’d probably shit his pants, assuming they weren’t already soiled by virtue of it being hard to wipe your ass when you’re fat.