I don't use "Social Media." It's pointless--like shouting into a crowd. When you want people to really listen to your words, you should speak quietly and directly to the people you are addressing. Social Media is perfect for a Blowhard Bully like Trump. They deserve each other. In answer to this specific question, Twitter etc. are not required by the First Amendment to let anyone say/write anything. It is NOT a "Public Space". Trump cannot force them to do anything legally--all he can do it to try to bully them!