I don't know if it's common thing to deny comments (by blocking people, close comments section, deleting comments etc) or not. But I do know for sure that some people can't accept comments easily and would rather fight back.
So for your question, is it fair or not? that depends on your definition of fair. For people who can't accept comments, yeah, denying comments would be fair for them. The issue is that they lose valuable feedbacks from other people which could be used to improve their games.
That being said, maybe you need to rephrase your comments or criticisms to make them sound more positive and supporting. Ex: instead of saying "I don't like the typos in this game", say something like "If the typos were fixed, the story would be better".