There are many more destitute people on the streets of Calcutta than in London and we don't hear of them looting and burning buildings. I have heard various accounts of the rioter's socio-economic makeup and don't know which of them are based on facts, but the way any disadvantaged group has made any real and permanent gains has been to prove their detractors wrong by facing the odds and succeeding, which also serves as an example and incentive to their fellows.
Why people justify destroying innocent people's property and wrecking their people's lives is beyond me. But to answer your question to the GP, if I could afford a Blackberry, I'm guessing I wouldn't feel justified burning buildings, beating people, and stealing their possessions. If I was starving and without food or shelter, it is conceivable I would descend so low as to steal, but if I did indulge I would probably feel pretty guilty. If my conscience bothered me as I expect, I would even try to make amends.
I grant you that a certain percentage of that is because I have not been surrounded by lots of peers who think it's OK to beat little old ladies, smash cars, and take things other people have earned. When everyone around you says some bad thing is OK, the element of shame and disapproval from others is eliminated. Conscience should still remain, though. And I hardly think the problem is to eliminate cultural and societal strictures.