True enough, an increase in the aggregate money supply places upward pressure on all prices, but never equally, never all at the same time. Nobody can say with certainty how and when currency inflation will affect supply and demand for each market. MARKETS ARE NOT FUNGIBLE. Nobody can say how, when and to what extent market substitutions and other market adjustments will factor into which markets as a result of the distortion. If apples increase in price by 51% and oranges decrease in price by 49% there is no way of disentangling all the factors to determine the effects currency inflation had on either. Isn't that convenient. And who can say whether oranges might have otherwise decreased in price by 70%, with apples remaining stable in price?
Apples and oranges are a REALLY POOR example because in fact BOTH have gone up in price. Way up. It's not a case of one food going up while others go down, as if it all somehow evened out to a mild increase overall. Some go up faster than others, but even we don't know all the variables. We just know that they're all on the rise and that NONE are really falling.
This gets into the problem with those who imply that aggregate averaging is somehow meaningful -- that inflation may really be benign, or "not as bad as we think" because, after all, the price of yachts and luxury commercial property fell by 35% while the price of food went in the opposite direction. And somehow that's supposed to make people who can't afford groceries to feel better? That's the real apples to oranges, the really nasty reality of thinking only in aggregate collectivized terms -- even when our Wonderful Wizards In Charge do account for food.
Again, it's not "THE ECONOMY", but "WHOSE ECONOMY" that is being affected. At all times. Currency inflation does not hit all goods and services with equal pressure or at the same time. So it's no wonder that a Keynesian-spawned moron like Krugman and his ilk, whose food budget is just another minor number (What, him worry?) thinks the way he does. These are people whose individual economies are not hand-to-mouth, check-to-check, week-to-week survival, so why wouldn't he be quick to point out nothing but averages and aggregates, while calling for more of the hair of the dog that NEVER bites him, and ALWAYS bites someone other than him.