The requirement is somewhat archaic. As with a great deal of Article 514, Section 514.11(A) was originally extracted fom NFPA 30 or one of its successor documents. The current parallel text in NFPA 30A, Code for Motor Fuel Dispensing Facilities and Repair Garages is no longer as stringent. (See Section 6.7)
The text does reflect the general anathema Articles 500 through 516 hold for multiwire branch circuits and not quite so obvious the fairly stringent bonding requirements in Classified locations. (They want absolutely no possible path for a potential ground fault) The text may be due for editing.