An organization of armed vigilantes fighting against whomever they decide is a "bad actor" wanting to "coup" "their" community? Sounds authoritarian.

Also, try to be less vague.
Who decides what a "bad actor" is?
What makes it a "coup" compared to just a change in leadership?
What makes it "their" community where it is also not the "bad actors" community?
What if you don't have any volunteers?
Where do you get the weapons from?
Who organises the training and how?
What happens if a volunteer won't participate in the training?