Interesting perspective. I observe that masked anarchists are almost always carrying weapons. It would be very hard to argue in court that an armed citizen who dropped one or more of them was acting imprudently - when screaming masked men with baseball bats are menacing people and smashing property in the midst of a riot all bets are off.
These anonymous, belligerent "tough guys" are only tough guys when they have the advantage of numbers and a disarmed ciizenry to exploit.
More Carlo Giulianis would set them straight.