Does it really matter if there are any rules or laws about this? No one follows them anyways.
true, just take a look at this site and the debate over "right turn lane". Is it for deceleration to make a right turn, is acceleration to merge and just how many miles can you travel in that lane before exiting? Have we not?
I would argue the same is true here, "the law says I can pass on the right". Like, "the law says I can make a right turn on red".
Frequently people don't really read the law, they merely hear the headline and the nuances escape them - like, you can turn right on a red light after coming to a complete stop AND there is no oncoming traffic. The law was implemented so motorists wouldn't be stuck waiting for a light to turn green when there was no traffic.
While I haven't read the law about passing on the shoulder, I'm sure it was done for a similar reason, to allow vehicles, were safe, to go around a vehicle stopped waiting to make a left turn (or possibly including a disabled vehicle.
I would bet there are some caveats about not passing an emergency service vehicle, and the speed, etc.
But, as I said, mere nuances. I can pass on the right, so I will.
BTW, TTFN - Ta Ta For Now, a Winnie the Pooh sign off.