> when no such central organization insists

No any such organization exists. It is a movement, and a description one can describe one's self or actions: "anti-fascist".

But of course, their logic for sanctioning-by-association would mean that they all - Trump, Bessent, Rubio etc. - with their innumerable contacts with "violent terrorist groups and regimes" everywhere around the world, and just themselves really - should have been sanctioned, arrested, tried, or just disposed of like the US does with so many it dislikes.

Yes. The president fomented a violent insurrection and then pardoned its participants (who should all still be in prison). He shouldn't be in office and you could similarly sanction his own social media platform, X and any other number of their supporters.