Does common sense have a place in the world of professional grading?

[Rob D.]

While browsing an auction online, I came across a complete set of 1952 Num Nums. (Even though it's a postwar issue, I think the question is relevant here.) Below are two cards from the set (scans are from goodwinandco.com). The Bob Kennedy is missing its coupon at the bottom; the Larry Doby has its coupon.

I've given this some thought, honestly trying to come up with an answer to this question: How can any grading company come up with the logic that deems both of these cards receive the same grade? I know it's a coupon that's missing, and the coupon was meant to be removed. But how could anyone not come to the conclusion that a card with its coupon shouldn't receive a grade higher to a similar one without, even taking into account the "intent" angle? It just seems so simple to me.

Please play devil's advocate. There has to be some reasoning that got PSA to this decision. I just don't know what it is.