Considering they could log out (or open a private tab) and view the content, obviously it wasn't access to the information that was fundamental but the act of the President taking a step to reduce someone's access.
With that in mind, the underlying host taking a similar action is either a) Okay because it's their system? or b) Bad because they're blocking or altering the message?
We're in this really weird spot of free speech vs private property vs public forum vs free access vs..
Imagine a future president picks a Catholic forum to make the same sort of announcements that Trump currently does, specifically a catholic forum that bans any advocacy of pro-choice discussion. It is relatively easy to find a similar forum on any side of a modern hot button political issue.
Twitter's upcoming option to limit replies is being touted as a politician's dream, but in the US it's likely going to be unuseable for the same reason
If you're going to make legal nitpicks, you should probably have a thorough understanding of the jurisprudence.
And I wish you were right. That was how I always read it too but we've found out repeatedly - and recently - that state & local governments (and state universities) can ban numerous things, contrary to the 1st Amendment.
I just ctrl+f'd for "public forum" and yours was the first hit. One thing in particular I would like to comment on is that post-Trump's election I started listening to some of my SO's legal field podcasts because I wanted less sensational analysis. I very distinctly remember a series on the Opening Arguments one where they went into some depth about why Twitter should be legally considered a limited public-forum (this was in response to some other Trump-Twitter hubbub at the time).
So, just granting that, how does potentially being a "limited public forum" change it's rights and responsibilities to it's users? What about the heavy US government involvement in these companies, how could that change the analysis? What about the fact that dominate platforms are able to control the narrative due to that domination? Doesn't that completely fuck up the free speech concept? "Everyone uses X, but you can't because we don't like you, so you can have your free speech over there in that corner where nobody is." What kind of dangers in the long run does this present? Why do these companies so easily fall into models of censorship, and what kind of future would that mean for the public? (not looking to actually get into the convo necessarily, I'm commenting on the meta of the discussion and wish these kinds of questions were being asked more)
I personally hate youtubes banner for controversial shit. It always links to some shitty ass Wikipedia thats been heavily controlled/edited. Wikipedia is just not a good source of info on controversial topics, (though looking through revision history certainly can add context of what is "missing").