Why should you need to disconnect the grounded conductor?

You might want to pull it for testing purposes.

If you are looking for illegal ground to neutral connections lifting the neutral would be step one along with the MBJ.

That said I don't understand what it really accomplishes, I have never seen any one in the field talk about it. It seems more of a construction specification of service rated equipment. 225.36

Now when we use the exception to 225.36 do we need to use two pole snap switches so we can break both grounded and ungrounded conductors simultaneously?

FWIW 225.38(C) mirrors 230.75

We've got a couple of jurisdictions here in SoCA that have you perform a "neutral to ground" continuity test (with the link removed) at final inspection.
This way they can verify that there are no grounding connections on the neutral anyplace but where they belong....At the service.
Resi services are done with the individual neuts disconnected from the neutral bar.

A good idea, IMO