What kind of people behave this way? Those who have come to think of wealth as an infinite pile from which everyone grabs as much as they can. This is where the ethos of the socialist left and hip-hop comes together.
What we are seeing in the British riots is this combination of young white anarchists/socialists and black underclass thugs. That happened in the recent Oakland riots, too.
Frankly, I think it's less accidental and fortuitous than the author appears to believe. Mob violence has always been one of the strategies of the left for destabilizing society so that it can take over.
The constant drumbeat of class warfare and race baiting plant some of the seeds which lead to this.
The mindset is that they rioters/looters are “entitled” to the fruits of someone else’s labor and if the government isn’t going to be the conduit for a satisfactory redistribution of wealth, they’ll forcibly take it.