Have you heard of Hamburg bombing of 1942? Why do you think Churchill killed tens of thousands of civilians? Why did one of the world biggest democracies, with rights and moralities in the centre of it, committed such an immoral action.
My version is, to piss off and humiliate Hitler, so he would retaliate with similar action. it worked, Hitler focused on bombing civilian targets in london, this enabled Churchill to save his navy and prevent german amphibious attack.
Hamburg was tragic, but at the end England was saved. Same here buddy, 9/11 made westerners rethink their policy. Without 9/11 the west would continue to back one or another group, they would continue to bomb osama hide outs from time to time or arrange convert operations for his capture.
9/11 made the westerners think that achieving peace in a disaster zone like afghanistan might be to everyone's interest.
Five years after 9/11 and five years of less anarchy for afghanistan. Five years that regional and western powers haven't shoved each their own maniacs to power. Five years without hearing the roaring of artillery and screams of children.
Whoever did 9/11 for whatever reason, I am telling you, it was damn good for afghanistan.