When someone creates a post he or she can select a muted category from dropdown list and post into it. If category is muted the user should not be able to post into it.
Disagree. “Muted” doesn’t mean, “Completely hide this category from me so that I never see it again.” It means, “Don’t show me these topics on the topic lists.”
I agree but I think the context of the request is a bit different, it is more like “If I have this category muted, why would I ever create a new topic in that category?”