Do you think it should be illegal for HN to moderate posts and ban users (without accepting legal liability for all user generated comments)? If HN can moderate comments, why not Twitter? If you think it's unethical for HN to operate the way it currently does, why are you still here? Maybe you should stick to your principles and delete your account.

This isn't an all-or-nothing type of deal. A company does not have to take responsibility for copyright infringement in order to have the right to moderate their own platform. I do not see what Twitter does as censorship and don't believe users should have the expectation that whatever they post will be amplified.