They are relevant to the concept that they give up certain private property rights in order to gain other legal privileges, which is a precedent for requiring that they give up other property rights (such as the right to censor on the basis of politics, etc.).

Property rights are completely irrelevant to the discussion on hand. 'Right to censor' is a made up concept. Companies and individuals have no obligation to publish something they do not agree with. Anti-discrimination laws also do not protect Trump here. He isn't singled out for his race, sex or religion. He's singled out because he incited a seditious mob that overran Congress.