Left wing paramilitarism thoughts
I have very deep suspicion that left wing paramilitarism will work about as well as right wing paramilitarism and likely far far worse overall. The right wing was most successful by pretending their paramilitary had nothing to do with them, bunch of lone wolves and the media was absolutely cool with that because they could not handle the truth after Oklahoma city.
Left wing paramilitarism thoughts
Also to be honest the infighting amongst the leftist can really lead to doom too, one big advantage the communist had in the Russian civil war was that the whites were just so completely incompetent both militarily and politically. We can't count on that good luck (plus the reds had the military rank and file on their side which I doubt we have today in the USA)
Left wing paramilitarism thoughts
Not that I'm saying don't protect your self or don't try to do things, just that it is dangerous to put our eggs in one basket when that basket is, in my opinion, flimsy. Foundation building isn't fun or glamorous but essential for something that will last. Look to our fascist foes who have multiply attack approaches (think tanks, christian religious, paramilitary, propagandist, business groups, civic groups and so on)