I think this quote from Dave Barry's article that Max posted is appropriate here:
That's what's so hard to comprehend: They want us to die just for being Americans. They don't care which Americans die: military Americans, civilian Americans, young Americans, old Americans. Baby Americans. They don't care. To them, we're all mortal enemies. The truth is that most Americans, until Tuesday, were only dimly aware of their existence, and posed no threat to them. But that doesn't matter to them; all that matters is that we're Americans.