You can follow these beliefs all the way back to the earliest times ~ (Check: Flying Garuda) ~
In our foray into Iraq there have been repeated events where one of the bad guys we've targeted is in a building or other location that gets bombed with massive amounts of explosives. Everybody turns into powder except the bad guy ~ and there he is trying to crawl away to do it all over again.
Just the other day the IDF/IAF used a 500lb, or 1000 pound bomb to blow up a Hamas' leaders home ~ ordinarily you can do a job on a house, even a concrete house, with far smaller munitions, but the IDF/IAF has this funny idea that to wipe 'em out you have to use the big stuff.
Ever wonder where they got that idea? Well, it's from experience. The leadership elite is harder to kill for some reason.
Eventually one of 'em is going to let us know what the secret is and then we can get rid of the whole nest.