Natural disasters are ubiquitous. Somewhere in the world, something is always happening... a tornado is touching down, a dam is breaking, a river is surging, an earthquake is trembling, a forest is burning. Some of these events become so routine, that local residents come to view them as quirky inconveniences rather than hellish disasters. Weathering them with a smile becomes a source of pride, an essential element of local character. Inclement weather becomes a feature, not a bug. The national media does goofy human interest stories about it. Locals hook their thumbs in their belts and say, "No sir, them there sulfuric acid geysers ain't never bothered us none. You just keep the kids indoors and wash the dogs with baking soda after you let 'em out."
"Wisdom is learning from other people's mistakes."
It isn't that the people left in New Orleans are stupid, they just miscalculated how prepared they and the community was for such a catastrophe. This isn't stupidity but rather ignorance. Given the general level of science understanding the general public seems to have I guess it is not a surprise. Generally speaking ignorance can be cured. Everyone learns either the easy way or the hard way.
There have been a lot of big disasters in the last few years. We need to learn from them and prepare ourselves. The last decade was quiet disaster-wise this one is shaping up to be rather more exciting.