I'm not quite as bitter as you are about rationalists, but it's certainly true that people get a lot wrong, and in particular, they're generally bad at checking on whether their means are a good match for their purposes. The planning fallacy is a good though unflamboyant example of people getting things wrong even when they have years of evidence that they underestimate how long it takes to get things done.

My guess about ISIS is a mixture of a desire for personal power and drama, combined with some hope that Allah will help make the Caliphate work.

Thanks for the pointer to "The Fire Raisers". Have an anti-Communism/anti-decadence story by Kipling on a similar theme: the Mother Hive.