A lot of this land is wooded bottomland and swamp. It is part of Cajun country, it is where the Acadian people took refuge generations ago when they got kicked out of Canada, because nobody bothered them there in the Atchafalaya basin. It has been a place where you could subsist off the water and all its creatures, hunting, fishing, etc.

It is not a place where greedy developers have sold people lots.

A better question is, why do people have to live below sea level in New Orleans, and if they do, why are their levees not strong enough to withstand a 'project flood' and, if so, why do their rural neighbors have to take the fall for them when the Mississippi rises?