You have a fundamental misunderstanding of the concept. It's not nebulous at all, it in fact describes a very specific approach, to the point that it might as well be a playbook.

Part 1 is a radicalization chain, where you have several layers of public figures with varying levels of public-facing support for your cause, who guide people down the chain by platforming people with more extreme public-facing views. So maybe a talk show host who mostly just points out obvious problems in our society, who occasionally brings on guest speakers who have slightly more specific framings, who themselves occasionally publicly support YouTube channels that pitch potential solutions.

Part 2 is consensus building. As people trickle down the radicalization chain, it's important to introduce them to new social spaces that present your ideas as obvious truths. This normalizes your radical ideas in the minds of your newly radicalized cohort. Casual "joking but not joking" comments are a basic staple of this, with guillotine memes and blackpill posting and Boogaloo jokes all serving to make the appearance to their community that their extreme views are normal, acceptable, and widely held.

Part 3 (which is somewhat optional) is targeting. Some prominent figure (likely one of those public figures on your radicalization chain) paints a far less vague target than usual: casually calling for people to kill all landlords is one thing, mentioning one specific landlord is a clear escalation from that. Ideally this is done without making any incriminating statements, which at least in the US is easy: as long as your don't make a specific plan, it's typically considered protected speech.

Part 4 is, to borrow some specifically leftist terminology, "propaganda of the deed", "direct action", or just "terrorism". With a sufficiently large pool of radicalized individuals, you'll have people all across the radicalization and "unhingedness" spectra. The "extremely radicalized, completely unhinged" corner is where you find your martyrs, freedom fighters, etc. They hear the targeting speech from part 3, and decide to take it upon themselves to do something about it. They commit some act of violence, and probably end up facing some extreme consequences for it, whether that means death, imprisonment, etc. Then, your entire movement needs to achieve 2 things: outwardly distance themselves from the "lone wolf" to avoid unwanted scrutiny or consequences, while privately lionizing them as someone who "did what needed to be done" in order to encourage the next one.

The elegant thing about all this is that what it lacks in cohesion, it makes up for in robustness. Since it's not a rigidly fixed organization, individual parts can take a fall without crippling the effectiveness of the whole. One lone wolf doesn't incriminate any other members, except maybe the person who announced the target, if they were sloppy about how they worded it. And if someone along your radicalization chain loses their seat in the public eye for whatever reason, you have plenty of redundancy to fill the gap, and they can probably find a comfortable position somewhere further along the chain once things cool off a bit.

Playing whack-a-mole with the people with enough prominence to plausibly select targets is probably the most legally justifiable way of suppressing a standalone complex like this. Most people along the chain, both participants and consumers, are pretty clearly practicing free speech and assembly. They make perfectly legitimate targets for rival radical movements, but the State needs to uphold basic human rights, so it takes a more precise approach. Focusing on the shotcallers, it's easier (not necessarily easy) to get creative with what constitutes a non-protected "true threat", rather than crack down on civil liberties as a whole.