I think you may be right concerning some of the people who may have stayed in order to loot and take advantage. Also, some welfare types who just assumed "someone" would take care of them. HOWEVER, I also know that there are good, decent people who had no choice but to stay -- people with no resources, small children, elderly, disabled, etc. Sadly, thousands of them are dead by now. Pray for the survival of these good people and do whatever you can to help.
You are quite right. Those that cannot help themselve need help in spite of those who will not help. But I'd sure like to see bad things happen to those trying to take advantage of the situation in order to loot, burn, kill and/or rape.
Also all of the emergency responders (police, fire fighters, hospital workers, ambulance personnel including medi-flight operators and more) and a lot of service workers, who were keeping some of the hotels open--and offering hospitality sometimes free to people who had nowhere to go. (Many tourists were stranded, because the city shut down the buses, and the cabbies had bailed.) Students, too, were left without a way out because most universities have little or no parking, so they didn't have cars--and were too young to rent them.