This was a Critical Mass event, which is why the bicyclists are taking up all of the street as a way to reclaim the streets and protest the lack of safety for riders under usual conditions. It’s not legal, but protests are never useful if they’re fully legal now, are they.
It doesn’t matter if a protest is legal. The word you’re looking for is “non violent”
it’s only non-violent until someone in a car drives into it tho (good)