'My Brother The Islamist' - Why did my middle class brother turn into an Islamic extremist?

It was a fascinating program, Ive watched it twice now. Id love to understand what made Rich turn into such a freak. He seems so full of anger. The other converts in the program like Ben and Dean seem much more laid back and cheerful. I wonder if something happened in his personal life to make him become so extreme, maybe he got dumped or something. I wondered why he often seemed to be in charge, he was speaking at the rallies, yet he had only been a muslim for 5 months. Perhaps people like him (white, middle class) are purposely targeted and brainwashed by the radical muslims to give their cause a more acceptable face. I just hope the next terrorist attack isn't perpetrated by english converts, it wouldn't surprise me.