The “peaceful protestors” are the human shields for the brick-frozen water bottle-fireworks throwers. The PP surround the violent crew. The PPs are up front in rows so the police can’t shoot bean bags at or mace the people throwing things. This renders the cops unable to counter the rioters’ weapons. The PPS will gang up on police that break line by getting close and shoving but not hitting with any weapons. They just get in the way as much as possible.
The strategy is well planned and very well executed. The police don’t really have an answer (that they are allowed to use) for it yet.
The key is identifying the leaders _before_ the demonstrations happen and get them out of action, even if it is for minor violations...
In places where Antifa is out every night, that should not be difficult.