Quality control is just as subjective as the next thing. If checker A thinks a smuge is acceptable, then it's acceptable. Checker B may not think so and have the device cleaned. All subjective because humans are checking the product and humans have a variying degree of quality and performance. The flaws in your computer are the simple flaws you cannot see. Maybe a logic gate in the CPU is slightly wrong, yet it passed testing. Maybe there is a stress micro-fracture on the hinge or maybe the logicboard is missing a retaining screw.
*sigh*
There are quality control tolerances. The product either falls within, or without, but there is no "subjective" measure here. If Apple tried to claim that scratches on a brand new product were "within" then I would return it. If my dealer tried to claim that poorly stitched seats were "within" then I would return it. Why? Not because of a problem with subjectivity, but a disagreement about the tolerances.
Toshiba, Panasonic, Asus, and other manufacturers apparently have a very different view on the appropriate tolerances for products and how they should respond to claims. So, I don't do business with them when I can help it.
Apple has staked their reputation on exacting quality control, and when you approach their staff about a problem, in every case (in my experience) they immediately respond by recognizing that the product is outside of the tolerances, and replace it for me. We agree about the tolerances.
Blah, blah, blah... It is a scratch. It is unacceptable. It ought to be returned, in my opinion. If you would like to buff out the scratches, be my guest. We disagree then on what consumers ought to expect of manufacturers, and how they should respond when a product fails to meet quality control standards.