I think in part the problem lies with the manner in which some parents have abdicated their parenting responsibilities to the state (or those they see as representatives of the state).
Part, perhaps. But the thing is that parents have been encouraged to leave it more to society since WW2, and there's actually nothing wrong with that in itself, but only if there is a strong identification between society and the state accompanied by the kinds of systems of accountability and social redistribution that make people feel included and in control.
But the UK has become more and more half-hearted about social democracy, almost as soon as it was introduced, and then the state has gradually withdrawn from its social obligations, leaving nothing in its place. Coupled with the hyper-individualism and demand for immediate gratification that has been encouraged by consumerism, this generates a low-attention span, aggressive, disengaged, amoral and sociopathic populace. In countries which retained the courage of their social democratic convictions or were more committed to them in the first place, particularly the Scandanavian ones, this social void has not been created to anything like the same extent. Sure, you get the occasional violent nutters (as we do in the UK too) but rioting... not so much.
This factors aren't confined to the people rioting, but in the richer classes, amongst people like bankers and brokers, sociopathy and amorality are almost regarded as virtues, even as they mess up the entire world, not just a few streets*.
*Disclaimer for the hard of understanding: nothing in this statement should be taken as endorsing or condoning the violent actions of the individuals involved in the rioting.
