> Please be advised that your platforms are rightfully expected to expeditiously remove all posts that have celebrated the political assassination of Charlie Kirk. Further, the authors of these posts are to be identified and banned from your platform, as well as any new pages they may create.

Without any citations of law to justify it, this is a remarkable claim. It could be that the statements are against the terms of the sites, in which case they have every right to remove/block the content and potentially remove the users (it's their service, after all). If these comments could be construed as threatening there might be some law to have the contents removed, but not to outright force the services to ban the commenters.