Censorship is a government preventing its people from speaking freely. If you really stretch the definition, censorship is a company preventing its employees from speaking freely. Someone that owns a public outlet (a website, a radio or TV show, a billboard) restricting what people say on it is not censorship. A regular user of a public outlet, such as the one you replied to, telling other users of that outlet what to do is not censorship, it is so far from censorship it's almost not on the same plane of existence.