While not condoning the attack on the World Trade centre, or any other terrorist attack, note the following:
In the Vietnam war the Americans were happy to drop Napalm on woman and children (as well as men). It is a horrible liquid that sticks to the skin and burns it.
They also dropped Agent Orange, a poisenous liquid that killed vegatation, but also had terrible side effects (that has also effected American soldiers as well as local Vietnamise)
The 10 largest arms manufacturers in the world are all American.
How many people in the world do you think have been killed by weapons made by American arms manufacterers.
Far more than died in the Twin Towers.
We feel sorry for the people in the twin towers because it was in New York and it was easy to video the events and interview the surviving families.
Does anybody make documentaries about the thousands killed in Iraq (both before and after Saddam) and interview the familes.
No, so it is easier for us to identify with the people in the USA than those in Iraq, Afganistan etc, but they are all humans.
The USA have been involved in virtually every conflict since the second world war (either there or supplying arms), it was only a matter of time before they got attacked.
I am afraid you reap what you sow.