I agree that the arguments he made are not supported by evidence, but this is our judgment of his paper, not a reason to retract it and prevent other people from reading it.

The fact that the paper is written in a scholarly tone is obviously relevant. If it was spam or "junk mail", or some sort of violent sermon or political philippic, then of course there is no reason for it to stay online. But it's not. It's obviously a real, genuine academic paper.