Last month, the British historian Simon Schama took aim at “Downton Abbey,” denouncing it in Newsweek as an exercise in “cultural necrophilia,” a “servile soap opera” and a “steaming, silvered tureen of snobbery.” (To which millions of American television viewers apparently replied, “Yes, and…?”)

Now, the British poet James Fenton has piled on, if more gently, in the generally Anglophilic pages of The New York Review of Books. In an essay titled “The Abbey That Jumped the Shark,” Mr. Fenton accuses the show not just of absurd plot twists, geographical inconsistencies and excessively buried gay subplots, but of brazenly promoting the class interests of its creator,...