the various assassination attempts against the president or the multiple attacks against ICE agents and facilities?

https://www.justice.gov/opa/pr/leader-antifa-cell-members-no...

Dunno, I'd mostly frame that as self defence from an increasingly hostile and authoritarian government and the actual, literal secret police.

Fighting back against people who straight up murder civilians in broad daylight is not something you can classify as extremism with any good faith.