What you really want is for the (seemingly large amount of) violent acts to not cloud the message of the overall protest.
But to try to do this by whitewashing the events, attempting to "manage the narrative" is not the right way, I think.
The dude came for the protest, lobbed a molotov cocktail into the PDX WTC, retreated into the camp and was arrested for starting fires there.
Was it better because he didn't lob his grenade into the camp? No... Does the story ring false because the reporter quoted the police involved? No...
http://www.oregonlive.com/portland/i...occupy_po.html
It's a sad fact that civil disobedience attracts a lot of scumbags and morons, but that's part of the whole thing, and can't be so easily dismissed. Attempting to manage this problem by saying it doesn't exist will only attract more attention to the next event.