[kahljorn]

*sigh* You're right, this is different than simple rebellion(when is it ever really simple, though), but the principal emotion lies the same. There's two ways this can go: either they've always wanted to be a terrorist, or the invasion of iraq triggered it. If it was the later, than it is essentially a form of rebellion. So what, they aren't calling themselves "the south", things are different there than you'd normally expect. Disheartened people flowing into an organization internationally reknown for hating america and it's allies isn't exactly some surprising thing, nor is it outside the scope of rebellious actions, especially when said country just got done invading your homeland.
In a place where america wasn't the favorite beforehand, what did you expect to happen?

Regardless, it was a result of poor moral structuring and even poorer morale. To me, that's rebellion, twitching under oppression or just following the voice of God... none of those are unexpected in the circumstance. Act surprised, but that's kind of a ridiculous way to feel. Did you think terrorists would stop being produced because america invaded? If anything, there would be more of them because of the "moral outrage" it represents.
Why do you think a terrorist decides to be a terrorist?