Nah, he's not claiming to know absolutely nothing. Any President is going to have to rely a lot on intelligence summaries. From what I understand, the CIAs reservations on the Al Qaeda - African uranium connection were buried in footnotes.
I just don't think this is that big a deal.
However, if you want to talk about whether Bush should have purged Tenet and other Clintonites from the CIA some time ago, that's a fair question. Tenet does appear to have reciprocated Bush's loyalty in this matter, though.
He'd be gone right now if this whole debacle really was all his fault (as they contend) and caused this much trouble.
The conversation would go something like "you ex rat sonofabitch, it's your gudddamm job to provide us with reliable data and you fuxed up, not pack your $**t and get the hell out of my sight. Look at all the trouble you you got us into".
Instead they're best buddies still.