I agree with all of that.
But there's another reason:
Unless we really have lost our marbles, we will not only have to ring a rebuilt NOLA with Cat 5 levees EVERYWHERE (like I said), but those levees will all have to be double/triple ringed and/or heavily patrolled IN ORDER NOT TO BE JUICY TERRORIST TRUCK BOMBING TARGETS.
The terrorists have just gotten one hell of lesson on the use of floods as a terror/economic weapon in NOLA. Imagine what the death toll would have been if there was NO WARNING AT ALL.
Culpable as I think Nagin and Blanco are (finally, even ABC has noticed), at least MOST PEOPLE GOT OUT!
And sadly, it appears the terrorists are/were already there with all the reports of shootings at emergency and repair workers!
The only good news is that NOLA is (was) uniquely vulnerable to this threat. We need to take it off the table -- but frankly, I'll be surprised if we do. The only hope I see to do the right thing is if the insurance companies start charging NOLA rebuilders a premium commensurate with the real risk.