Your first drawing has an error.
Couple things you're missing about AC mains electrical.
Current must be equal and opposite in each cable or conduit...
that is to say, all the currents (polarity considered) must sum to zero. Your route would be a triangle, with each side of the triangle carrying current in only one direction - imbalanced.
The reason that's bad in AC is the same reason transformers work on AC - the vibrating electromagnetic fields (EMF) thrown by the wires. When equal and opposite, the electromagnetic fields cancel each other out, and it's not an issue. Otherwise the fields are trying to induce onto anything metallic. That takes energy which adds impedance which creates heat - either in the wires or the inductees. It also causes vibration, including in the cable, which can metal-fatigue and crack copper... narrowing the wire at the crack, causing localized heating and as it devolves, arcing which causes tremendous localized heating.
We don't like unplanned heat.
You also hear about people who have anxiety about EMFs - they may well be in a miswired house. Maybe humans can't feel EMF but animals definitely can.
We switch hots.
In an AC world the idea of polarity may make no sense. It is because the system has been bonded to keep voltages relative to earth at sane voltages. The transformer holds the hots at a particular relationship to neutral. Neutral is called that because it is bonded directly to earth at the service point.
As such, if the entire system is fully assembled and working properly, neutral voltage is within a couple volts of earth, and so neutral isn't particularly dangerous. The hot wires are dangerous.
So we switch hot, so we are able to more-or-less fully de-energize what we are switching — again, assuming the system is working properly. If a neutral connection fails, all bets are off!
In a pre-NEC-2011 switch loop, where a spur cable goes to a switch, if the white wire needs to be re-tasked to be a hot wire, it must be the always-hot wire. It also must be marked with black or colored tape, but almost nobody does.