Ten years ago, less than two dozen angry barbarians killed about 3000 unsuspecting innocent Americans. What I find surprising about this is not that it happened, but that this sort of thing hasn't happened more often.
The Islamic world has a strong "victim of the West" narrative. It is deeply upsetting to them that they are not the dominant culture in the world, and they have fabricated a whole alternate reality that preaches that this is not due to any failings in their own culture, but rather a grave injustice inflicted upon them by the West though underhanded means. It is true that the West, through colonialism both subtle and outright, has been meddling in the Islamic countries, so the "victim" narrative is not entirely unjustified.
So, in 2001, a bunch of them got fired up and lashed back, killing as many Americans as they could. Surprise, surprise.
But what about all the other failing cultures in the world? There are many other societies in the world that live in crushing poverty. There must be a lot of rabble-rousers around eager to tell all these people that their problems aren't their own fault, someone else is to blame. And most of these societies have been manhandled by the West at one time or another, so it shouldn't be hard to construe a reasonably credible "victim of the West" narrative in any of those cases and sell it to the masses.
9/11 is not an isolated incident. There have been many other attempts to commit mass murder against the West, but to my knowledge, they have all been perpetrated by militant Islam. What about all the other losers of the world? Why aren't they participating in this game?