So they intentionally designed the dock to damage the console instead of just designing the dock in a way that makes sense? This would be the first consumer electronics device I'd ever heard of that would be intentionally designed in that fashion.
These justifications are too much. Honestly if this were true it would prove Nintendo to be malicious instead of incompetent.
Design is a series of trade offs. Whether it's iPhone antenna placement or removing a 3.5mm port or using a plastic screen instead of a glass one.
There is no one right decision, because all decisions have implications for durability, cost, and/or usability. Nintendo probably went with plastic for both cost and screen breakage, and then when they thought about scratches from the dock, they said: "hey, we'd rather have the bezel scratched than the screen" and then designed that into the dock. Maybe a better dock design could exist, and I suspect others were prototyped but this one was the one they landed on.
People assume Nintendo only hires dumb people or something.