The equivalent of their level of military organization would probably not be minivans, it would be something like rolling out barbed wire, laying smoke, digging trenches with machines, mortar teams, snipers and ordinary riflemen. Something which in practice would be impossible to deal with and which would immediately necessitate negotiations.
I'm not propagating for that though, but I do think there is a similarity to the learning process-- how the Swedish peasantry chose to develop this capacity and strengthened it until it was useful.
Think of humans as these epsilon-greedy things, which with probability epsilon go and explore the payoff space. I think people see that things are being done to them that cross the line of screwing them over to something like crushing them, and this makes attempting to get back at those doing the crushing to get them to back off rational. Thus I think that it's reasonable to expect an exploration of violence to see where good payoffs can be had and where you can deterrence.
It should be noted that his assassination attempt followed a year where no less than 3 people set themselves on fire in protest of another arm of America's industrial grinder. Which is to say that the most recent act doesn't represent a sudden escalation, but is instead emblematic of a progression from despair to anger. Several billionaires also predicted this progression, warning their peers to ease up on their behavior. They're not listening, and some "ordinary people" seem ready to make them.