Let's be brutally honest here. It's not about justice. It's not about winning the War on Terror. Terrorism won't go away. Even Al Queda won't go away. Oil won't suddenly be plentiful and the ice caps certainly won't re-freeze.
It's about revenge. It's a feel good moment, like when Emperor Palpatine gets the shaft in Episode 6. (In the Lucas universe, every spacecraft must have one or more large shafts which lead straight to the nuclear reactor. A bomb or main character is required to fall into one of these at least once per episode.)
Of course, the elation of that moment was quickly dampened when Luke pulled off Darth Vader's helmet to reveal ... Uncle Fester! Don't believe me? See for yourself ...
And, like Star Wars, this story doesn't begin with 9/11. There are all those weird early episodes that can't compare to the original trilogy. It began with bin Laden working in a construction business on the desert planet of Tatooine. Back then, he was a good guy, resisting the evil empire's invasion of Afghanistan, and happily hooked up with Queen AmeriDolla. But once that exploit was over, he was seduced by the dark side, and he turned on us. From then on, it was a series of more outrageous and terrifying ... uh, terrorism. Until now.
There's nothing wrong with a good revenge yarn. But reality is still out there.