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.
This gives me an idea. How about every bike gets retrofitted with a large titanium hook. The idea is that if you hit my bike, your car is pretty much totaled. Not just that but if you really hit me, the hook passes thru the radiator, thru the firewall and into the drivers asshole.
Put a little LED light on it as a warning beacon.
A tactical pool noodle with a very abrasive end should do the trick.