I could just as easily blame the British for the Balfour declaration... which led to the current Mideast strife - which led to AlQaeda causing 9/11 which lead to the military interventions in Iraq.
My point is - its too facile to blame the Bush administration for everything. Look further back...
Al Qaeda being caused by whatever they were caused by has absolutely no bearing on the actual decisions made after their attacks on 9/11.
9/11 happening doesn't determine what the outcome of 9/11 will be in terms of policy response.
The response of the Bush administration was important, and led to many (I suspect intentional) negative outcomes for the American public in general.
To just wave it away and say - it comes from earlier in history - strikes me as a bad idea at best, and a way to avoid responsibility for your actions at worst.
Predicting events is one thing, but there are certainly better ways to predict the results of policies.