That's the old "broken window" fallacy from basic economics: If you break a window it's good for the economy because the workman and the glassmaker get paid to replace it...so let's go break all the windows and really create a boom!
When I hear senior Fed officials (who certainly know better) making very similar assertions, I worry.
Well, we didn't break this window, Katrina did but to think the economic consequences are going to be bad is just silly. Is it going to lead to economic growth? No, of course not, but it's not going to be a net loss either.