There is a complicated thing going on here -- the social media companies argue on one hand that they're not responsible for what their users say, that they're just a means of transmission, but on the other hand, they do take *some* responsibility -- they ban Trump. They have taken a step that, say, Verizon has never taken. If you want to conspire to something illegal on Verizon, they won't stop you or even try to stop you; if the FBI finds out about it, they may get a warrant to listen in on your calls, but Verizon doesn't do anything but comply with the terms of the warrant. Facebook and Twitter have now taken a step beyond that, and on their own responsibility, have begun limiting what Trump can say, banning his use of their means of transmission. By doing that, it seems to be they have asserted not only a responsibility but a right. And if they have the right to do that, it seems to me that they have now abandoned the pretense (which is all it was) of being purely a means of transmission, and are now more the equivalent of a newspaper...and so could be sued for things like libelous statements carried on their electronic pages.