As far as I know, that’s a Twitter restriction, not a legal restriction. It isn’t a restriction I would impose if I ran Twitter, but Musk’s free speech rights include the right to decide what he is willing to publish on a platform that he owns. Those who disagree are free to use a different publisher. (There’s a reason I’m posting here rather than on Twitter.)
As far as I know, that’s a Twitter restriction, not a legal restriction. It isn’t a restriction I would impose if I ran Twitter, but Musk’s free speech rights include the right to decide what he is willing to publish on a platform that he owns. Those who disagree are free to use a different publisher. (There’s a reason I’m posting here rather than on Twitter.)