As proven by the loser creep who killed James Foley, who has been identified as a former rapper who had a at worst upper middle class up bringing. The scumbag's from Calgary who were raised upper middle class to moderately wealthy and were given every opportunity.
These people are inhumane thrill killers, they're not disenfranchised and marginalized youth, they're psycho paths and the only solution for them is a un marked grave.
As for the recruiting of them, I'm betting the pitch, beyond, hey you get to kill people in the worst possible way and rape anyone that you want and god will forgive you and man won't be able to prosecute you, is that someday soon you'll be able to do the same thing in your home country.
http://nypost.com/2014/08/24/masked-...le-identified/
It takes a different kind of dirt bag to slowly saw the head off of a man, or rape and shoot kids.
Personally I don't care about understanding their root causes, I think the root cause is pretty apparent. Spend money on intelligence with the end goal of extermination.