I hate that distinction so much. Baseball stats would be so much better off if we stopped arbitrarily dividing between "earned" and "unearned" and "hits" and "errors." I think there's a use for those stats, though. If there's a runner at 2nd with 2 out, and the pitcher throws a routine ground ball, and the fielder airmails the throw to first and the runner scores, that isn't the pitcher's fault. If he gives up a ground ball of the exact same speed and difficulty, but it happens to be placed exactly in the hole between two fielders, is it his fault? If he gives up a fly ball to shallow outfield and the outfielder gets a poor jump?