There was the incident of a protester holding a boombox over their head, and getting shot in the face with a "less lethal" munition that cracked their skull.

Another where a person was riding their bike away from a protest and got hauled into an anonymous van and held without cause.

Self defense is ok, these actions are not. One "protester" being violent does not warrant collective punishment of all/any protesters. It warrants defense from, and the arrest of, the violent ones.