No, Twitter Still Isn’t Subject to the First Amendment — Even If a Judge Said Trump’s Account Is

Joshua Geltzer was quoted by the Washington Post on why Twitter, despite the judgement regarding the President's account, isn't a public forum for First Amendment purposes:

In determining whether a space is a public forum for First Amendment purposes, judges apply a multipart test. One factor in the test is whether the supposed forum is owned or controlled by the government. Twitter, as a private entity, fails the test. For Twitter to become subject to the First Amendment would all but require the government to nationalize the company — an extremely unlikely prospect, said Joshua Geltzer, an expert in constitutional law at Georgetown University.

“The decision finds that President Trump, as a government official, created the type of public forum on the @realDonaldTrump feed that only the government can create, and to which the First Amendment then applies,” Geltzer said. “The decision may have implications for other government officials' blocking of critics on social media, but it doesn't even come close to making all of Twitter a public forum, as the vast majority of the Twittersphere is not being converted into a public forum by government actors.”