Are you confusing Y'all Quaeda with the Gestapo? Wtf. Even if 100 militias somehow defied everything we've been seeing for decades and somehow evaded getting caught early in the planning phase due to the surveillance state, what makes you think anything they'd do wouldn't be shut down by military police within a week?
It sounds almost like you're getting off on a weird horror fantasy from a super shitty movie.
A lot of the people brigading are actually alt-right dipshits from other servers. Some are left-wingers in denial ... and when this thing blows up next year, they might die. :(