Nostr alone won't protect you from government censorship because your government can arrest you for breaking the law, regardless of what platform or protocol you use. Nostr does protect you from corporate censorship, however. This is more than enough to make Nostr useful as a censorship-resistant protocol. While there are some limits to what (liberal) governments censor, there is no limit to what platform owners can censor, and they do arbitrarily enforce stupid rules. They have the right to do so, they own the server. We have the right not to filter what we write and read trough the whims of a few rich individuals and Nostr is the way to exercise that right.
This is wrong. Private entities can't do censorship because that would violate the Constitution.
You have that backwards.
"The constitution", much like "the law" means absolutely nothing whatsoever unless you specify a jurisdiction. I can't be familiar with all constitutions. What country are you talking about?
Of course I'm talking about my country: Portugal. Why would I tallk about other countries’ law?
Because nobody was talking about any specific country, let alone Portugal in particular. What part of the Portuguese constitution do Facebook, Twitter and all other mainstream platforms break when they remove stuff on their own servers, engaging in corporate censorship? Are those platforms inaccessible in Portugal? Because if not your point seems to be either irrelevant or wrong.
That's precisely because nobody was talking about any specific country that I've said what I’ve said. A stupid and wrong generalization was being made... I have no problem believing that in some less democratic countries, it is legally permissible for a private entity to exercise censorship over citizens in general, or over the users of their services. However, fortunately, there are countries where such censorship is illegal, and one of them is Portugal. In Portugal, if a private entity censors a citizen, the citizen has the right to: A) Get the removed speech or message reinstated; B) To be compensated for property and non-pecuniary damages resulting from the censorship; C) Obtain a compulsory pecuniary penalty for each day of delay in fulfilling the obligation to restore the censored message or speech. The above legal regime is the result of various legal provisions, mainly enshrined in the Constitution of the Portuguese Republic, the Civil Code and the Code of Civil Procedure. I'm not going to give a detailed analysis of all the legal precepts involved here, not least because some are procedural in nature, and neither is this a law lesson nor am I being paid to give one. I will say, however, and in direct response to your question, this: the aforementioned regime is constitutionally established in Articles 18 and 37 of the Portuguese Constitution.