There have been numerous analyst and experts over the years that have discussed root causes of extremism and terrorism, but this is almost a new breed. Political, social, and economic oppression has certainly bred all kinds of criminality from organized crime, to criminal gangs, to terrorists, and to extreme political movements. But even then this simply does not answer the why to this level of inhumanity and cruelty. I think in cases like this we can ascribe these root causes. I am strongly in the conviction that if al-Qaeda did not exist, these individuals would be somewhere else committing sadistic acts; either as serial killers, mass murders, torturers, or other craven acts of violence.
Zacarias Moussaoui in the end turned out to be a very mentally unstable person, probably bordering on insane. I think it is telling that it appears this specific movement of al-Qaeda seems to attract the psychotics, sadists, and mentally ill in the world. It is simplistic to just say they are evil, that label could be applied to anything we do not agree with. I think in the case of these individuals to say they are evil is simplistic as well, as it is by all appearance that they are psychopaths, and I mean this literally.
The irony was that it was acts such as these that turned the Sunni tribes ,involved in the insurgency, towards the U.S. to form an alliance.