Civilian militias have an enormous advantage over organized militaries. Guerilla tactics.
Yes, special forces employ them, but never the less, you’ll never see a special forces groups throwing IEDs on insurgent convoys.
Unlike civilians, organised militaries have rulebooks to follow.
This is true especially in authoritarian states with centralised decision making. See: the six day war. When communications were out, Arabs became mindless drones and the morale was in the toilet. Perhaps not the best example because that was organised military vs organised militaries. However, for Israel, everything was at stake. It was either victory or total annihilation.