I would say that it's not about whether the actor is a government or not but about whether the action is coercive or not. If a private individual personally thr

I would say that it's not about whether the actor is a government or not but about whether the action is coercive or not. If a private individual personally threatens to physically harm someone for their speech, she is engaging in censorship just as much as if she was a legislator passing a bill to that same effect. If a government school refuse to teach a certain fact, it's not engaging in censorship any more than a private individual who refuse to teach the same fact. Not communicating a piece of information and not helping others in communicating a piece of information is not censorship. Censorship is preventing others from communicating a piece of information by force. Facebook is not doing that, they have just decided not to help communicate some information. Another example would be that you would not be censoring me if you removed a political bumper sticker I placed on your car, even if you leave other bumper stickers placed there by other people in place.