"hinging the decision on whether your legs or your wrist is turning is illogical"
No it's not, it's recognizing the psychology between "big push with foot makes go fast" and "pressing button makes go fast".
Besides, if the only thing that matters is speed, then logically you'd have to require normal pushbikes to register as well, once cyclists are able to pedal sufficiently fast.
> recognizing the psychology between "big push with foot makes go fast" and "pressing button makes go fast".
And what is the psychological difference? As far as I'm concerned when I'm using torque-sensing pedal assist, I'm just pressing the button with my foot. The distinction between throttle and pedal assist is non existent in my eyes: pedal assist is just pressing the throttle with your foot.
Motor wattage and top speed is what matters.