As long as there a people who think there's only one way to do things and anyone not doing it their way should be killed, we will have terrorists.
That "we are creating terrorists" crap is, well, crap. We aren't twisting anyone's arm and saying "become a scumbag, piece-of-shit murderer of innocent people." Their religious leaders are.
It is more on the lines of:
Every action, causes a reaction.
The Iraq study group did mention that the CIA, I believe, said that terrorism world wide had increased since the War in Iraq, to some of its highest levels on record.
What we don't know is that if we had stayed in Afghanistan, fighting the terrorists that were responsible for attacking us, and had not pulled back our forces... and redeployed them and our resources to Iraq, that terrorism would not have increased at the same levels....so I do think this is a hard thing to confirm, it is more speculation.