HN also has fairly strictly enforced guidelines. Do you think dang et. all 'don't believe in free speech'?
HN has a very specific and limited topic range that is allowed and documented. There is some subjective things in what is allowed, but it is generally understood. People are not complaining about that. Nobody is suggesting HN should allow general sports news for example.
Twitter on the other hand is a general forum and so it should allow a broad amount of topics. If Twitter was a specific and targeted platform for cat pictures nobody would have an issue if they banned politics.
HN is very highly moderated and you could even say tone-policed, and that is a major part of why many of us here like it.