No-one is entitled to have a window manager on Linux either, but I'd probably still be using a Mac if there weren't any. The OP of this thread is not, to my understanding, making a moral claim about how Gruber should or shouldn't have comments - he's saying that the inability to comment, combined with Gruber's factual inaccuracies, frustrates him sufficiently that he no longer pays much attention to the blog. Is he allowed to make that decision? Or is Gruber entitled to his attention?

That requires almost no attention at all. IIRC, that's a large part of the reason why John doesn't want comments on his blog.

You'll have to take that up with him; I'm afraid that my insight into the minds of complete strangers is rather circumscribed.