Posse Comitatus means that, except in emergencies, the state and the Feds can’t use the military to enforce the law.
You’re thinking of Vigilance Committees.
You are confusing the Posse Commitatus Act, and the thing called Posse Commitatus.
Every community has the lawful right to form a possee commitatus.
But I guess you dod not read the Wiki link I posted. Go back and read it.