Well, I will give some of the points they have here. However, I agree that they should have opened the classification up to all cars and not just American ones. Such nationalizations are pointless in the modern globalized car industry.
Depreciation is a view of the market, and is not the fault of the given automobile. It has absolutely no bearing on how good or bad a given automobile is.
Given that, I don't even think they necessarily picked the worst in each class, much less in the overall marketplace. Not including the Sebring/Stratus? As bad as the Grand Prix is, those are worse.