Each riot was sparked by an event - the Canucks losing the Stanley Cup, and a black man killed by the police in a way that raised the community's suspicions. The rioters in both cases are young (teens and early 20s) people. The police are not designed for, and ill-equipped to quell riots and prevent innocent people and local buildings/stores from being harmed.
[ASIDE: Domestic police forces ought not be militias, armed to the teeth, and bent on suppressing the citizenry; this assume-the-worst-of-our-people attitude is a self-fulfilling prophecy.]
There's one other thing the countries have in common: while both invest heavily in, and are reputed to have excellent public education systems, their schools are becoming increasingly mechanistic and factory-like. Success is measured by test scores; effectiveness is based on numeric data; and students are viewed as numbers (vs. humans), and assumed to be cheaters and prone to bad behavior, read: mistrusted.
In good times, economic success can overcome these failings, but with increased unemployment and more people falling below the poverty line, no-one is present to model a "peaceful national character and an accepted moral outlook" or the idea of civility for young people. Parents are too busy making ends meet, and there are few "good" influences in the media, or in our increasingly aloof neighborhoods.
Their most formative experiences happen whilst in school, and if the "texture" of that experience is "you'll be held back if you don't do well on the tests"; "we know you're a truant or are cheating and we will catch you"; and being treated as a data point and not a person, how do we expect them to grow into anything but disenfranchised young adults, who when presented with an opportunity to rebel against "the man" will gleefully take it?? This BBC interview of two young British rioters is a classic example of the result.
Why doesn't this happen as much in America (which has an even more mistrustful public education system)? I think it's because the local police forces are more violent and better armed.
[ASIDE: Domestic militia can discourage violence, but at what cost? Prime Minister Cameron just said, "There are pockets of our society that are not only broken, but frankly sick...It is a complete lack of responsibility in parts of our society, people allowed to feel that the world owes them something." His remarks are political peacocking, and by weaponizing his police forces, he creates an even greater rift with the citizenry. Being 'tough on crime' is a failed strategy, as evidenced in America, which boasts the highest percentage of incarcerations on the planet, but no corresponding reduction in crime.]
It is regrettable that politicians can't focus on root causes. In all three (and many other) countries, our children are victims of an increasingly dehumanized education system. The powers that manage (districts, departments/ministries of education, etc.) and influence (Gates, etc. Foundations) public schools are filled with too few real educators, and too many MBAs, whose training in micro-thinking leads to disastrous macro-outcomes.
"Take care of the little things, and the big things will take care of themselves" is a practice in most MBA programs (in their parlance: what gets measured gets done, just focus on optimizing your piece of the business), and is one of the worst things to happen to schools (and corporations) over the last generation. "Penny-wise and pound-foolish," or "missing the forest for the trees" are much more apt, but frequently ignored.
When you manage teachers based on their students' test scores, you demand that the teacher ignore the person in front of them, and focus ONLY on their preparation to answer a set of questions on a piece of paper. Learning is not a requirement; correct responses are.
More and more parents choose a school for their children based on test scores, in the mistaken belief that that's a "good education."
Is it at all surprising that young adults aggressively rebel when given the opportunity? Is it at all surprising that they have a diminished sense of civility and respect? Which adults treated them with civility and respect? What behaviors did their "models" exhibit towards them when they were most impressionable?
Learning is an inherently human act - the more you separate the person from their education, the less educated and "human" our younger generations will be.
The people to blame for the riots in Vancouver and London are not the kids (they are merely accountable), but rather the adults (parents and educators and policy makers) who created the education system in which they were dehumanized.