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.
Yeah, but this is a little like protesting against gun violence by juggling loaded handguns and putting everything on the safeties working perfectly. You don’t protest an unsafe amusement park by going on the unsafe rides standing up.
Point being, most people would probably not want to serve as the example of what not to do. Most rules/regulations are written in blood, but most people aren’t volunteering to be the ink to pen those regulations.