New Orleans had a cultural legacy that it left behind when it was destroyed. It is very important that its cultural value be restored the best that it possibly can for future generations to be able to enjoy the city as well. The rebuild process has taken some time, but the cultural value should live on there.
The history of culture of New Orleans are deeply ingrained in the American psyche. There's no reason it shouldn't be rebuilt after the devastation there, and there's no reason that the federal government shouldn't take active steps participating in the city's time of need. This country made an effort to rebuild the Twin Towers after their demolition, why not a whole city?