There was no rhyme nor reason; just pure opportunism. You only have to look at the demographic of those arrested to see that it is massively varied and not just kids with no fathers and a single parent on benefits. From memory, some of those arrested (and charged?) include:
* a teaching assistant
* students and undergraduates
* an olympics ambassador
* a millionaire's daughter
Now, I have seen some genuinely passionate individuals trying hard to put across their voice and stating that where they were once a silent part of society, they now have a voice and seem to have people (the media) listening.
This may be true for some of the 'rioters', but it was mostly mindless - driven by greed and selfishness. One guy was saying that there were no opportunities and no hope for the future for many youths - which may, or may not be true. But mindless violence and theft of goods is surely not the way to a future of hope, is it? Neither is people being murdered.
People can try and put a logical explanation down for the rioting, in order for people to feel like "there's some logic" but I think we all know that it's removed from the truth of the matter. Parents have a big part to play in setting examples for their children, but then we all have to set good examples in society, even if we don't have children.
Then again, it's easy to be objective from a perceived ivory tower, isn't it!