Josh put it better than me. But yes, if a critic's job were simply to give a thumbs up/down, they would be utterly unnecessary -- we have Amazon, Goodreads, Yelp, and a zillion other venues for that. A good critic (like Pauline Kael, e.g.) can illustrate or illuminate the work in a way beyond just telling me whether I should spend my time/money on something. There are critics I never agree with (like James Wood) whom I respect because of their degree of engagement and thoughtfulness, and others (like Anthony Lane) that I really enjoy reading because they're funny or good writers, but I don't think they're good critics. At this point Lane reviewing a Star Wars or Marvel movie is just a stunt because we already know he's going to make fun of it.
Van Der Werff is partially right about MM, but it's not like anyone set out to do that. Most shows use the dynamics of writers' rooms in their storylines. There are a ton of writers' room dynamics in Breaking Bad, for example, especially the Walt/Gus/Jesse triangle. And Walt is exactly like any number of embittered TV writers out there. In the case of MM, it just so happens that the advertising and television industries are a lot alike (as MM itself often shows).
