I'm not saying Americans are ignorant. The same would apply to Britain too.
You have to remember how a lot of these people live: no TV, no electricity, barely surviving.
I had a friend who spent a couple of months in Morocco last year. She stayed with a family out in the country and it was beyond 3rd world. They had like 10 kids, and at suppertime, they filled this big bowl with food and passed it around 1 by one as they only had one spoon. They all slept in the same room, had no TV, couldn't afford newspapers etc. I'm pretty sure they would've had no idea about 9/11 either. The two countries aren't so different, financially speaking.