The people who didn't evacuate were poor and didn't have means of transportation out of the city. If you call for a HUGE evacuation, you need to have hundreds of buses to get people out BEFORE IT HITS and then a lot of this problem would have been avoided. Any idiot could tell you that. 
 
The Mayor of Chicago (an idiot), I know for a fact, would have had every single person out of the city who needed help getting out. Its a thing called foresight and Mr. Prez has none. He's too busy looking overseas and spreading Christianity.  
He couldn't allot that extra $20 mil to restore the levys in New Orleans BEFORE tragedy struck. He had to wait until afterward and spend TRILLIONS of dollars.  
After Katrina struck, everyone saw how horrible it was. THREE DAYS LATER the president starting paying attention saying that he was finally briefed on the incident. "Hey idiot, could you not see the people DYING on your television or your fly-over in Air Force One?????" I find that v. hard to believe. He had to wait to get briefed on it??? 
another thing that I find worth thinkinng about is the way that other countries are thinking of this tragedy: 
http://www.uruknet.info/?p=m15399&l=i&size=1&hd=0