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.
Meanwhile, in Germany: §1 StVO
StVO § 1: Das Auto des Menschen ist unantastbar
pretty sure that’s true everywhere that has signed the vienna convention on road traffic, so like 86 countries