No need to pussyfoot around with sarcasm -- he comes right out and says it.
Nagin said what he said because he needs "chocolate" voters who don't think critically to not remember precisely how he never had those parking lots full of school buses issued forth to move people out before the hurricane, to re-elect him. Nagin is counting on the racial loyality and stupidity of NO blacks to re-elect him. Otherwise he feels vulnerable.