Something to keep in mind...
In any society that isn't a totalitarian one, an evacuation and assistance operation of the sizes of Katrina and Rita is going to involve a lot of chaos.
It would be a lot easier if mandatory evacuations WERE mandatory, if private transport, homes, supplies and buildings could be commandeered at will, and other efficiencies of moving people and supplies heavily enforced.
It's a free country. There's going to be some mess. Frankly, I'm impressed things are going as well as they are. Try and stay away from the idea that the government is, or should be, God.