Just checked my switch and it had those smudges on the black part of the screen... But they were just smudges lol. Can wipe them off with your finger. Checked the dock and the smudges were caused by rubber in there towards that bottom. So... Didn't see anything that could possibly scratch my screen.
No idea how tf these people managed that as there is literally nothing sharp in there. Just smooth plastic and rubber at the bottom to keep it from getting scratched or to keep it in place I assume. Either these people were careless, purposely scratched it themselves, or got defective switches or something.