This means, of course, that each and every protesters must be culpable for the actions of very other protester
YES. Absolutely. Unequivocally.
When the peaceful protest turns violent and you remain...not dispersing when required...you are culpable.
This ain't rocket science.
It's civics 101.
If the group of which you are member violently attacks police...if you are a peaceful protester...it's time to disassociate yourself from that group with a quickness.
This supposes that the protest is in a small, restrained area of town, not a March blocks long? This also indicts the students at Kent State University fifty years ago. The National Guard fired into the unarmed stud ntsmjust as classes were changing and the group of students appeared to grow larger. Three of the dead students were killed in the parking lot of Taylor Hall, still holding books.
Just shows that the cops are not infallible? The protesters gassed in Lafayette Square on June 1 were peaceful. The Australian TV crew was peaceful. The elderly gentleman shoved to the pavement in Buffalo was peaceful. The students clubbed by cops in Philadelphia were peaceful.
And, ironically, they were all protesting excess police force.