So you think the delay in help is incompetence rather than maliciousness? You may be right about that, though it sure would be more convenient for Bush and his cronies if the black people were killed, as it would save them the trouble of preventing them from voting, as is usually the case.
When the people were told to leave New Orleans, no one did anything to get poor people out. When one is warned of a natural disaster, the warning, by itself, can be useless, if the people who are warned do not have enough money to leave or enough money to stay in a hotel somewhere else for however long the disaster lasts. And the idea that it could not be predicted is a joke, given that the levies were designed to withstand a category 3 huricane, and it was known that this was a category 5 huricane before it hit. See:
http://www.cnn.com/2005/WEATHER/09/01/katrina.fema.brown/index.html
But, hey, the Republicans who are running this country could all be morons instead of intentionally getting people killed.