Maybe he shouldn't turn of comments, but i hate to say that a lot of people even can't give a positive feedback to him about how to make better video's. I mean look at the comment some people write at news articles, wishing that that cop was hit because all cops are bad, or similar things. Looks like a lot of people can't behave online, guess that if they where sitting next to the same person they wouldn't dare to say the same things.
That's a good point, there are scores of keyboard warriors out there, and while I wouldn't class someone attempting to correct factual mistakes as being one, the fact remains that a lot of people seem to think they can say whatever they like online, things they wouldn't have the guts to say directly to someones face...