I thought that is what the diagram showed (voltage flowing through a device (bulb filament) and up the neutral leg).
It seems like the code was written for working on a live circuit... or rather written in case someone willfully or ignorantly works on a live circuit.
Isn't it moot if the circuit is off, confirmed off (metered), and locked out properly. (again, not arguing for using the neutral for switching)
The code is (IMO) logical. Switching on the hot leg turns off the supply of voltage/shock hazard at the switch, just like turning off your garden hose valve stops the flow of water downstream of the switch.
Your contractor friend had a misunderstanding of current flow. The original message you posted was
...was that IF the circuit was still live and you grabbed the neutral wire in the switch box and touched the grounded box you wouldn't get shocked.
If you grabbed the neutral wire in a box properly switched on the hot wire, you can touch the box without issue as it is bonded at the panel - no voltage potential difference. Contrary to your friend's belief, if you switched on the neutral and were touching something downstream of the switch, you WOULD be shocked if you touched between neutral and ground, as now neutral is floating up to line voltage through the energized load.
