I can understand the delay and the bureaucratic incompetence in trying to get aid to people. But this is just beyond belief...
Suburb Ok'd Decision To Block New Orleans Evacuees
The City Council in Gretna Louisiana has passed a resolution supporting a move by the police chief to seal off a bridge that could have been used by thousands of people in New Orleans to evacuate. Gretna is a largely white town while the vast majority of the evacuees in New Orleans were African-American. The town's mayor Ronnie Harris said "This wasn't just one man's decision. The whole community backs it." Hundreds of men, women and children were turned away as they tried to cross the bridge over the Mississippi River. There were reports that officers fired gunshots over the heads of some people trying to cross the bridge. New Orleans Mayor Ray Nagin criticized the town's move to close off the bridge. He said "We allowed people to cross ... because they were dying in the convention center. We made a decision to protect people.... They made a decision to protect property."
From LA Times