Both men are lonely sons of Allah, yearning for paternal attention, even affection, in a polygamous culture in which fathers have too many children and little incentive to pay close attention to any one of them. This is devastating, especially to sons, because the culture overly values fathers and men, and grossly undervalues mothers and women. Thus, the attention a son may receive from his mother (if she is not sent away, as Bin Laden’s mother was) does not make up for the missing and longed-for father.
One can only gawk at the amazing demographics and psychological dynamics this puts into play. This does not alone explain terrorism. But it can go some way to understanding drives and needs that might underlie a culture and push it in certain directions.