How Does New Orleans Justify Demolishing 47 Schools?

The following argument is puzzling to me because the City seems concerned that the Census figure will reduce the amount of federal aid they receive. Well, shouldn't the City receive a drop in federal aid if they feel the need to demolish 47 public schools?

A population estimate of 240,000 released this week by the Census Bureau is off by about 60,000 according to City Hall officials, who noted that a discrepancy of that size can drastically reduce federal grant allocations that are critical to an array of social programs. Such grants affect everything from education to substance abuse treatment, they said.

If one was truly interested in the population returning to pre-Katrina levels, they would ensure that the returning families have schools for their children. Those schools that are set for demolition were not just sitting idle before Hurricane Katrina. If everyone returned to New Orleans, wouldn't there be a school shortage?