SPO, I agree with your assessment. Censorship doesn’t have to be governmental to be censorship. Parents censor children. Television networks employ teams of censors, for their own product. Social media platforms censor content on their sites. These are all within the normal English usage of the word censor.

I don’t think that “censorship” only refers to governmental action. A private university does censor, even though it is not a government actor, and how do you deal with private university speech suppression that violates law (e.g., Title IX)?

I think you would just add “official” to “censorship”–also, there is another element–obviously, the First Amendment has a cultural element. What Joaquin Castro did, while not violative of the First Amendment, is antithetical to the spirit of the First Amendment—particularly since one of his goals is clearly pour encourager les autres.

Joaquin Castro is a censor.

The statement is true—it’s just misapplied. Obviously, raising a a false alarm to cause immediate panic in people who have no ability to assess the validity of the alarm is actionable.

“Fighting words are not free speech.” You can’t walk up to someone and call them the “n-word” and claim free speech.

But when people use these narrow things to try to block speech, or worse yet, arrest people for it, it is sickening. At the end of the day, when someone is arrested for the exercise of free speech, we lawyers can say “the system worked” when the courts ultimately get it right–but that’s really not true. And we know it.

Ken White’s omission of that argument is very likely due to his disagreeing with you about it. He has repeatedly held the public/private actor distinction to be vital not just legally in setting the bounds of what the Constitution restrains, but also ethically. It is often commendable, in his view, for private organizations to refuse to let themselves be used to disseminate certain types of vicious messages. I can’t disagree with him on the principle of that, although I have more than once disagreed with his evaluation of how the principle plays out with respect to particular actors and institutions.

All of which is good reason not to use the term “censorship” when referring to Twitter terms of service, private university rules on clubs and speakers, and other controversies when not involving government action or pressure.