I understand why NO is there and I have no problem with them rebuilding but I want to know why they didn't maintain the levees better. I heard that they had sunk by many feet. Why aren't they constantly kept up?
"Why aren't they constantly kept up?"
My understanding (I have some friends who used to live in the area) is that the situation was more complex than just the levees. They have needed for many decades to do some major work down there and the state lawmakers kept saying that they didn't have the money, the federal gov't should do it. The feds offered to match funds but the LA lawmakers wouldn't get serious about putting up money for it, they wanted it done for free (i.e., the feds do it).
Someone would have to pick up the bill for that. Even though doomsdayers have been warning for years that New Orleans could get wiped out the human mind tends to lapse into denial. If it hasn't happened yet, people tend to think they'll miss it in their lifetimes. They judged wrong on this one. Living on low ground always carries that flood risk, although the big storms only come every so many years or so.
The US has a lot of overdeveloped coastal areas taking that risk.