Both of these points were covered in the article. It’s not about public/private fora. They argue (with case law) that when the government uses a private venue i

Both of these points were covered in the article. It’s not about public/private fora. They argue (with case law) that when the government uses a private venue in a public way, it becomes public. Additionally they only argue that @realDonaldTrump is a government account because the government itself has stated that the posts from that account represent official statements by the President. More generally, they mention cases where the FOIA applies to emails sent through a private account when the communications are discussing government matters.