The tl;dw is that there is no standard and never has been, so the idea that there's a "correct" orientation for these outlets that's been warring for dominance with the cute one is a myth.

The rest of the video digs into the claimed benefits of turning them upside down, and finds that they're quite small and probably outweighed by the inconvenience of the sheer number of devices that assume that you're using the cute orientation.