It's that vile book they read and that syphilitic pedophile they worship.
L
I'm not being flamy, but who cares what their book says if your putative leader is such a fat cowardly dork that he hides in a bunker but urges others to die for him?
I mean, if their spiritual leader said, "I'm Steven Al-Sagal Al-Chucknorris al-Blackbelt, and I'm ready to lead you wonderful jihadis into battle with the infidel, anytime and anywhere! Follow me to victory!", it might be a little easier to understand their suicidal zeal.
Just asking.