Now while I don't know the tradition of Southern Africa, Arabian peninsula and the Mesopotamia area (didn't know what else to call it), I strongly doubt that it encourages people to stab each other just for fun, or blow themselves to take other's lifes as well. Highly unlikely.
What I believe to be an actual problem is a lack of parenthood. I'm not just spitting this out, I'm saying this from my own experience and from what I've witnessed. Kids and teenagers who had irresponsible and 'mild' parents, parents who approved everything, always defended their kids and never really cared what they do - those kids got into some serious troubles. It wasn't the tradition that got them to extreme, but a lack of religious knowledge, and any knowledge at all. They were simply manipulated.
This is how it works, at least here. There are fairly small groups that have divided themselves from the official Islamic community, and they have their own mosques and institutions. What they also got is money, which they use very cleverly. Volkswagen Sharan isn't called the wahabi car for nothing. They use their money, influence, a bit of psychology and aim weak personalities. They have a strong bond inside the community, it's like a cult, which it practically is.
Those new recruits are used for such evenents. Every one of these groups has a highly educated leader that is even more respected hailed.
The point? It's not all tradition. It's mostly manipulating. The guy who attacked US embassy in Sarajevo is a clear example. Was a lunatic back then, now he's pretty much rehabilitated and realises what a fool he was.