Definition
vigilante
noun [C]
a person who tries in an unofficial way to prevent crime, or to catch and punish someone who has committed a crime, especially because they do not think that official organizations, such as the police, are controlling crime effectively. Vigilantes usually join together to form groups.
Just because I happen to agree that they fulfill the definition doesn't mean that I don't approve. Heck, if I lived on the border and the Minutemen were patrolling my property, I would give them sandwiches and coffee.