I think 9-11 was pretty traumatic for America as a whole. Would people be supportive of the whole Iraq war mess otherwise?

America didn't have war on their ground for few centuries prior to that (Pearl Harbour doesn't really count as it was attack on a military base, imho). And now you have something like THIS, new type of warfare, new type of terrorism. I think even Europeans are messed up from that. America lost a good deal of their perceived safety. It was end of an era. It was traumatic.

As how it effected each and every individual... it is up to them. Noone can really judge.