This is off-the-cuff, so might be a bit flaky, however people have asked:

1. It is generally wrong for the government to censor general forms of speech purely upon the grounds of the speech occurring, or its form, or its content; this goes double if and when they ignore context such as “artistic expression”
2. It is generally acceptable, if worrying, for the government to censor specific speech based upon well-defined and established bad intent, bad effect, or bad consequence of the words; for instance in the UK that might include “inciting racial hatred” or similar, but could also reflect a less justifiable / more overly broad definition such as “obscenity”. Generally there should be an actual law / primary legislation to back up the legitimacy of doing this. If there is not a law / if such is delegated to secondary legislation or regulation, it’s a bad sign.
3. It is generally wrong for a platform to deplatform someone purely upon the grounds of who they are (“we don’t like your face”); but see also that…
4. It is generally acceptable for a platform to deplatform someone’s content where it violates the well-defined and established terms of service of the platform, likely including prohibitions on content that breaks local laws; this may reasonably extend to a person being wholly deplatformed too if they are a known, serial or repeat offender (“don’t break house rules”)
5. If a platform has terms of service and fails to enforce them, or enforces them selectively, then there may be may be valid criticism of their behaviour; however remember that TOS are a blunt instrument which cannot possibly predict every circumstance where they may be applied (“…but he’s the President of the USA”) so some generosity is also required.

You have a right to free speech. Your right does not provide you with a free pass to indulge in criminal activity. You don’t have a right to a Twitter (etc) account. They don’t have to give you one and they can kick you off if you’re abusive. They ought to be consistent about doing such things.

Getting the entire Tech industry to shun you? That’s special.