Actually, you’ve nailed it.
For centuries Islam exported much of its crime problem by encouraging the psychopaths and sociopaths to wage jihad on the border. Win/win for them.
It’s fairly obvious ISIS is attracting these types to itself from all over the Muslim world. Where else do such types not only get a free hand but actually rewarded for such behavior?
What kind of human being sees such things, and thinks, “Got to get me some of that?”