Not hardly. It’s a privately owned forum. It’s legal for the owner and administrator to censor, just as Jim can zot leftards off of Freep, and a football team owner can fire a player for taking a knee on the field, and Roseanne could lose her sitcom over a tweet. She had contractual clauses she could have used to push back, but chose not to. But that’s contractual, not free speech. First Amendment only applies to government action against speech.
That’s not how Twitter works.