I find it incredible that presumably no one tried using a MacBook charger before this shipped. If they did and didn't document the shortcoming that's arguably just as bad.

Surely a not insignificant number of customers have MacBooks? If I was writing some test specs this use case would almost certainly feature, given the MacBook Pro's USB C adapter must be one of the most widespread high power USB C charger designs in existence. Especially when the stock device does not ship with a power supply, not like it was unforeseeable some customers would just use the chargers they already have.