Looks like we have two diverging points here. One, Katrina was a tragedy, most of us know that. Two, football taunting is common, a vulgarity among the masses who cheer on games.
Do you really believe people holding those signs didn't think Katrina was a tragedy or that New Orleans people are lesser human beings? I for one, don't and take it for what it is, toungue-in-cheek taunting.
What was the Almann Brother's Bands album named after Duane ran his motorcycle into a Peach truck?
Eat a Peach. (although, the band members say they named the album after a quotation by Duane)
People, be self-deprecating enough to find humor in any situation.