Whether it's 'we' or 'they' is really beside the point in this situation. New Orleans was not a direct hit and the storm was a cat 4 not a cat 5. The storm made landfall at Waveland MS, which put NO on the west side. Surely, the threat of a cat 5 still exists and still SHOULD be dealt with, as you seem to be pointing out and as I would agree.
But the situation as we have it is much worse than it might have been had the maintenance of the levee system continued under the Bush administration. The fact is that every president since Johnson has provided funding in the budget for the maintenance of the existing levees. There've been a number of unsuccessful proposals to beef up the levee so that it could withstand an even stronger storm, but as it is simple maintenance might have prevented the breach that occurred, especially when you considered that the levee held until after the blow. The democratic senator from Louisiana, Mary Landreau, did in fact plead with republican leaders to keep funding the levee maintenance, but it was dropped.
That said, the levee situation is separate from the issue of the people holed up in the Superdome and the Convention Center. None of those people drowned, but some of them (and we don't yet know how many) did die from dehydration and lack of medical attention. We now know that FEMA turned back a convoy of Wal*Mart trucks carrying water for those people as early as Tuesday, and also refused the service of a M*A*S*H ship that was nearby and prepared to dock at New Orleans.
We might argue over how responsible George Bush is for the disaster at the Convention Center and the Superdome, but the responsibility of Michael Brown and Michael Chertoff is beyond dispute. Brown is utterly incapable of dealing with anything beyond a minor thundershower, and by his own admission Chertoff gets his information about disasters from newspapers. Those two blithering dolts have no business being in charge of anything.
If it's democrats you want to blame, there's plenty to go around in that party too. You can start with the mayor of New Orleans, who by the way was a republican until he decided to run for that office. He's the one who made the survivors at the Superdomw stand back and wait while the wealthy guests at the Hyatt Hotel boarded buses to get the hell out of town.
"I think younger workers first of all, younger workers have been promised benefits the government promises that have been promised, benefits that we can't keep. That's just the way it is." George W. Bush, May 4, 2005