I have lived in New Orleans before, during and after Katrina.
I was a first responder during the hurricane so I had to stay through it.
There were some people who were genuinely grateful for being assisted through the event and those that wanted to kill you for whatever food, water or medical supplies (mostly the narcotics) you may have in your posession.
(I work in the medical field.)
It was the only time since being in the Army that I had to carry a firearm while I was working.
Was it bad before the storm? In some parts sure, not so much in other parts.
New Orleans has always been diverse in terms of socioeconomic strata and culture.
Was it a bad place to live? I'd have to say not; I'm still here.
After the storm our "refugees", a majority from the lower income brackets, read "culture of poverty", did cause a lot of trouble in the places they moved to. And, oddly enough, during their absence, New Orleans was never a safer place to live. Pretty much everyone who didn't leave had jobs and enough of a financial safety net that their homes got repaired soon after the fact, despite the gouging contractors. (I lost half of my home so I can tell you first-hand.) The crime rate was never lower.
Now it is rising again as the people return and the per-capita crime rate is reaching new highs.
Mind you, I am not saying that everyone that left was a bad person. Just saying a disproportionate number of the criminals evacuated (and subsequently lived off of FEMA assistance for as long as they could) and are now returning.
There is also quite a brain drain in the medical field. A great majority of the medical practitioners here prior to the storm have fled to other states. I know several physicians and nurses that did this and they report that they are quite happy with their decision. If you or someone you know is a medical professional and is looking for a job, New Orleans has plenty of openings still. One of my jobs is hiring new professionals at one of the few open hospitals here- I can't fill even one third of my positions.
I know, that was a rather rambling rant, but I hope is speaks to the topic at hand.
Have a great day!