I believe Matt C is trying to allude to perception and what is factually right or wrong. We need to be aware of what is right, and what is wrong. No one out there does horrific things just because they, well......can. They do it because the action they want to perform or have performed is justified in their logic, a logic that can be derived from their religion, political beliefs, personal beliefs, learning instutions, or simply "eye for an eye." Some of the largest and most violent atrocities were committed in the name of the "greater good." Hitler didn't set up concentration camps just because he felt like it. Stalin didn't kill 20+ million people just for the sake of "evil." Often, they thought they were on the side of the righteous, and the opposing forces were evil despite being factually right to prevent more murder and atrocities.
The 9/11 hijackers are not heroes. They are factual murderers. Flying planes into buildings to kill several thousand innocent people is mass murder. I don't give a shit if some whackjob religious fanatic in the desert thinks it right and justified. Perception is not fact. Could our long-time involvement in the middle east have contributed to the events of 9/11? Yes, I believe that is difficult to debate against. If we weren't in the middle east and had a general isolationist policy, would 9/11 have happened? I think the chances would have been diminished. Again, what happend on 9/11 was murder. Killing people in response to (Insert: Middle East military/political involvement, Complete backing of Israel and it's policies, importation of "offensive" Western culture...take your pick) is not a solution.
