I'm with Greg, I was pretty sure it was Bane's people who were doing the looting, not the people of Gotham.
That would make more sense, but then why does the movie waste so much time showing Bane calling on the people of Gotham to rise up and "take back their city" from the rich? If they all just IGNORE those speeches he gives at the stadium or in front of the prison, then what's the point of them?
It doesn't exactly prove Bane's point that Gotham is decadent and worth destroying if it's only him and some prisoners that are really making it that way.
Maybe the prisoners helped fuel
the riots, but I still think we're meant to believe that much of the general population helped out as well.