Why?
They would not be arresting thugs who beat up elderly veterans that's for sure.
Rock concerts usually hire Hells Angeles for security at concerts, particularly outdoor concerts. The Rolling Stones only uses Angels as security. They are untroubled by accusations of excessive force or civil rights violations.
We have a thug culture in the streets. The only way to counter that force is with a superior force. Law enforcement with rubber bullets and bean bags is NOT a superior force. Vigilantes have always been more effective than law enforcement who have rules to follow.
Ask an old timer in Las Vegas as to whether nor not Vegas was better off with the mob in charge? I don't know whether he's still alive or not, probably not, but there was a waiter who worked in the casino restaurants. I met him at New York New York. A real old timer he was with the mob as an enforcer in the day. He wore a ring made of amber with a spider in it so naturally everyone called him Spider. He would tell stories of the old Las Vegas when the streets were safe, the strip was fun and everyone made money.