The Americans obsession with terrorism is unbelievable. You can't blame it all on one thing.
There are many other ways than FS that can teach terrorists to operate a large jet. For example videos and books that can be purchased in almost every pilot shop and some book stores and video stores.
In my opinion I think one could learn a lot more by watching videos of the crew flying from A to B and explaining the basic instruments and what has to be done to fly the plane, than flying Flight Sim on the PC.