I don't see large groups of vigilantes forming unless and until there's some signal from (eg.) the Feds that they aren't going to be imprisoned for defending themselves against the people currently destroying cities. Without that assurance you can be sure these lefty governors would be calling in the National Guard the second one of these groups formed, and who do you think the Guard would be going after? Why the "far left Nazis" who "agitated against the 'peaceful' protests" of course.

Problem is I don't see that sort of signal coming any time soon.