It doesn't need an Oxford comma. The full meaning is already crystal clear with no possible confusion.
Anyway, that's his opinion. 99.9% of the population will not care either way..................unless, as a result of his complaint, a few (say 2000) get minted with an Oxford comma and released into circulation. Then Sir Philip might experience an unexpected surge of popularity amongst coin enthusiasts. Hey, I just throw that one out there as a wildcard.