I suspect people feel he gives a negative impression of lesswrong. And he will not go away with downvotes. Trouble is that it's not just that we disagree with him; often he is behaving in ways that are, not even wrong. If he were doing something wrong, it would be simple to say, "that is something wrong; instead of doing wrong you should do right like X". By being uncannily off, we can't even help.