I don't know if this is either a cynical or optimistic idea, but I don't know if those groups truly believe that throughout the ranks. That is why you often hear about payments to the family of suicide bombers. They aren't simply doing it for their religious beliefs, but also to help out their family. The same family that would have a 50% chance of death if the particular example virus from the article was released.
Or another way to put it, why is the pope-mobile bulletproof?
Almost all of them committing these atrocities for religious reasons. The Chinese government has treated Tibetan Buddhists horribly for decades, but you don't see any Tibetan Buddhist suicide bombers. There have been some sects of Buddhism in the past that have done horrible things, but in general it's harder to become a Buddhist suicide bomber than it is to become a Muslim suicide bomber. Some religions condemn violence of any kind. For example, I doubt anyone could be a Jainist suicide bomber.
If you don't believe me, hear it from the horse's mouth. Here is a video from a Muslim peace conference in Norway:
http://www.youtube.com/watch?v=bV710c1dgpU#t=45s It will take five minutes of your time, but I think it shows best how sincere these people are.
Or another way to put it, why is the pope-mobile bulletproof?