The exception would be if Twitter was ruled some type of public utility, like the old broadcast frequencies (in a very confusing and ineffectual way), though that would be a good thing.
There are more suitable concepts already available and in use like "common carrier", which have worked reasonably well where they've been applied.
Or you do what Trump's EO 13925 was aiming to do, which is make it easier to argue that Twitter has engaged in "editorial conduct" and thereby forfeited its "safe harbor" protections - under "Section 230" - from liability for other people's content.
[1]Twitter is presumably trying to do what it can try to stay ahead of whatever the
new government might have in mind regarding Section 230
[2] …
Edit: I suppose, I find it hard to believe that Master Dorsey actually gives a shit either way about Trump tweeting this or that which can be construed one way or the other, but find it very easy to believe that he'd like to take the opportunity to signal that he's a good boy who'll proactively censor stuff without the government having to actually
tell him to (now that the Bad Orange Man and his threat of enforcing Free Speech are out of the way). That for some of his users it will be like the 2012 Olympics come again is, maybe, a nice bonus.
