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.
Only protest where no one is inconvenienced and you can easily be ignored, mkay?
What’s fucking bonkers is car infrastructure. Highways trap me in place all the time when I want to talk a a walk or cycle.