Certainly not all but a great many were the drug dealers...the drug users....the thugs....the homeless...the mentally ill....people who had neither the resources nor the intelligence to leave the city. People who had no where to go nor the motivation to go there.
In other words, the people who were left in New Orleans were the minority whose behavior is normally kept in check by the people who left. When the grown-ups left, the children got to ransack the house.
It is also an informal fallacy to compare the poor of the US with the poor of Bombay. Those two groups of people live very different lives in very different circumstances.
By and large, this article is pure intellectual dishonesty.
One important point made which you don't need to be a pure intellectual for: evil is a jack in the box and it shows its face once in a while.
The picture that was painted in my mind by all this more resembles that of an isolated household comprised of many pets and an old lady who suddenly dies, cutting off all the deliveries of the pets' needs.
After a few days the pets have trashed the house, messed the floor and are fighting over the sparse meat left on the corpse of their once mighty queen.
"By and large, this article is pure intellectual dishonesty."
In my opinion, he said precisely what you said his essay was missing...but he did it with intellectual incisiveness, grace, stunning language and a great logical probity. Maybe it's just me.
Dalrymple, who has searing intellectual honesty, imho, notes exactly that. The poor of Bombay have not been funded with state-provided welfare for generations, and have not been subjected to the intellectual dishonesty of affirmative action and race-baiters, as Dalrymple notes.
The Mayor of NO said that drugs flow freely in NO, and the looters were druggies jonseing out there for anything to cut the unease of sudden withdrawal.