Not sure if serious or satire.
But in case of the former: This "one cartoon" is, by any meaningful definition of the term, a work of art. A lot of very smart and very sensible people devoted their entire lives to the study, interpretation and appreciation of art over the ages.
Those people most definitely made our collective human experience infinitely richer.
Or, to put it simpler: Didn't Roger Ebert had anything better to do with his time than watch a bunch of movies?