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 is not.
Cars follow the rules of traffic. This means you know basically what they will do. These people are just a mob. Look at how many of those bikes just cross solid lines. This is no where near the same. We can’t make progress if we start acting irrationally.
Also, cars don’t drive on the wrong side of the road into traffic and through red lights.