I don't think we disagree quite so much. Yes, it took time for ISIS to appear on the scene because even the US needed a lot of time and effort to screw things up so badly as to make them possible. But it was all perfectly predictable from the biggest screwup of them all: Bush invading Iraq.
And no, he can't blame it on the CIA. Richard Clarke, the counter-terrorism 'czar' at the time, told us that within hours of the 9/11 attacks, Bush, Cheney et al dismissed his opinion out of hand that it had all the hallmarks of al Qaeda, and to go away and come back with "proof" that Saddam did it. When Clarke and the CIA couldn't do that, Bush et al told them to come back with "proof" of Saddam's WMD. One way or another, Bush and Cheney were going to invade Iraq and they weren't going to let mere facts stand in their way. We all know how that went. And now we're living with the results.
Saddam was far, far from being a saint, but he ran one of the few secular governments in the region. He'd be the last to tolerate Muslim terrorists (Sunni or Shiite) on his turf, or cooperate with them anywhere (which was why the accusations of his supporting al Qaeda were so ludicrous). Remember he attacked Iran not long after their theocratic revolution, and that instantly made him our best buddy even though we knew perfectly well he was using chemical weapons. There's a famous picture of him shaking hands with Donald Rumsfeld. He didn't fall out of our good graces until he invaded Kuwait and threatened to monopolize the oil supply. That would have been an intolerable assault on freedom and democracy.
Having already stomped every last dinner plate and drinking glass in that particular china shop into dust, we now seem to think that if we just send a few more bulls over there, they'll eventually stomp it all back into fine dinnerware. Experience (and some critical rather than wishful thinking) would seem to indicate otherwise.