>>Or is it the nurture of fundamental Islamic philosophy?
Both - when Islam is recognized to be a hierarchically organized selective breeding program. One desired result evidently being a genome that is no more able to control its obediently aggressive behavior than pit bulls or cockfighting roosters.
Human Nature is predictable. Being predictable makes it exploitable; and religionists are especially adept at that. Observe how the sheeple of Rwanda, for example, were pacified and corralled in missions by one vestigial arm... to be hacked to death by another.