Having lived in that area where the hurricane hit the hardest, I also find it difficult to understand any lack of preparation. That includes basic knowledge. They would not have needed to go 200 miles to reach a safer area, 20-50 miles inland would increase their safety dramatically. It was an unusually strong and fast storm, but preparation is (or should be) done before they even identify a storm.
I experienced a strong hurricane in that area when I was a teenager, and my parents made bad decisions and were not prepared. We barely made it out alive. I know how many people think (or do not think), and there is little excuse for not getting off of the beach and inland a few miles. Not to mention having basic necessities like water and non-perishable food.
I stand by my assertion - and not that I am defending people who actually are able to prepare or leave, but choose not to, then run into trouble.
However there are a lot of people who simply do not have the financial nor perhaps the logistical means to prepare or get out of harms way. This includes the elderly, those with health problems, the disabled etc.
This has studied and proven many times over and is nothing new to this century nor the USA.