Dave Moulton (of course) gets it:
Critical Mass in the US needs to cease, it no longer serves any useful purpose.
If no one is responsible, then everyone is responsible. It is time to protest against Critical Mass, to urge people not to participate. The idea has run its course and is no longer valid. It is no longer cool to be a part of a lawless mob that disrupts the normal way of life, pisses people off, and worst of all perpetrates violence.