It's a staging/logistics move, I think. Moving them to the Super Dome means you only have to open one route out of the city. Same principle as FedEx.
Plus which, you know you've got dry places to put thousands of people, even if it is horrific in there.
You are correct. Think triage, figure out who needs immediate care, who to place in line, and who to assign to clean up the crappers.
Related:
http://www.nola.com/newsflash/louisiana/index.ssf?/base/national-50/1125405843191800.xml&storylist=njkatrina
Posted at NOLA.com at 4:01 pm central time.