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.
Oh, the driver’s feelings were hurt by a slight delay?
Fine. Here’s a better solution. Molotov cocktails. Any driver that pulls this shit gets their car torched.