Social Media Websites Could be Public Forums
It isn't new. It shouldn't be surprising. If you are a politician or a political body, you cannot use social media (e.g., Twitter or Facebook) for official purposes and block certain people from accessing the social media.
The latest politician to fall afoul of this prohibition is President Donald Trump (Knight First Amendment Institute v. Trump, No. 18-1691-cv (2nd Cir. July 9, 2019). But, he certainly won't be the last.