I'm going to wade in here and ther rest of you slap me down (please be gentle, tho
) if I'm wrong.
People must have something to believe in. This appears to be especially true if their lives are rife with hunger, poverty and general misery. In order to go about with the every day business of survival, they must have *something* to hope for. This is precisely the 'in' that people like bin Laden take advantage of so shamelessly.
If you were faced with grinding poverty and little chance of it ending and you perceived your neighbor as living much better than you, you would naturally envy the neighbor and perhaps come to blame him for your misfortune. After all, aren't you both god-fearing men trying to support your families? This goes on for some time, and then suddenly a charismatic man comes to speak or you hear of him and his message is one of hope and justness. All you need do is follow his tenets--which have been revealed to him by god himself, mind you!--and you will have a seat in paradise with virgins awaiting your every wish and prosperity as you have never before experienced! And since this revelation has come from god himself--and you have no reason to disbelieve that, isn't the messenger himself obviously blessed with prosperity!--you as a righteous man feel obligated to follow. It is your duty to god.
This obviously applies to Islam today. It also applied to the Roman Catholic Church of the Dark and Middle Ages (tho not limited to those times, certainly)with their various Inquisitions and other 'cleansings' of 'non-believers'.
Luckily the vast majority of Muslims and people of all faiths do not readily bow their heads to these charismatic radicals, but rather rely on the words of their own clergy and those revealed by their own readings and revelations. The silent majority do not speak so loudly against these, IMO, because there remains the secret hope that they might be reconciled to the original teachings. Or, more understandable perhaps for us westerners, one simply does not speak of the crazy auntie in the attic for fear society will cast the shadow on the entire family.
My .02
Garnet