So seriously

Where is the downside for these folks who comprise the "flash mobs" and rioters and such?

They are already essentially cut off (by their own behavior) from being productive citizens....They are (generally) drug users, even if it is just marijuana....They likely already have already got a felony or two on their record, so what is one more? They are likely (by their own actions and lifestyle) unemployable...

They have been taught by example (leftists and unions (but I repeat myself)) that they will still get what they want if they demonstrate and chant loudly enough...So their chances of starving to death due to our society cutting of their source of income is unlikely...They have been taught by the left and the unions that they can demonstrate bad behavior and get away with it...disobey the laws with essentially zero consequences... no negative economic impact to them.Worst case, they spend a few months in prison and add another page to their rap sheet, making themselves even more unemployable

Failing to follow the social contract has no negative issues for them. No impact. No negative effects. They don't even know what the term "social contract" means.

And until there are significant negative consequences to their actions they will do so with impunity. Until they are taught that they need to behave in order to get freebies from their fellow citizens...that stepping from the path of righteousness will result in the permanent loss of their lifestyle, they have no incentive to behave.