9/11 killed some 3,000 if I'm not mistaken, other terrorist attacks rarely kill more than 50 each.
AIDS killed an estimated number of 2.1 million people in 2007.
The UN estimates that starvation and poverty kill 25000 people every day (that's some 9 million in a year).
What is it that makes the relatively few who die of terrorism so much more important than those who die (mainly) in Africa? You could have one 9/11 every day and still not reach the number of casualties of starvation or aids.