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’s a protest. Showing how dangerous the streets are to cyclists (and how many cyclists use the roads) is the message. A protest that challenges law and inconveniences people peacefully is how they garner attention (hopefully as a prelude to change and improvements).
So yeah, ignoring a lot of traffic laws.
Thank you. It was an honest question, downvotes are fuckin hilarious lol