It is notable that critics found [The Grey] considerably more admirable than the life-affirming, panoramic saga of Les Misérables—found it more admirable precisely because it is tedious and small and offers the “message” that life is meaningless and rather horrible and yet nonetheless, all too short. This seems like a rather stupid criteria for enjoying art. I mark myself as unsophisticated for having liked Les Misérables—but what is more adolescent than the notion that futility and horror are the secret truth of life? Certainly the majority of life is anything but; no one spends most of their life thinking or acting as if they believe that all this is truly insignificant. If anything is the secret truth of life it is hope: grandiose, impractical, and with us to the last. Yet critics valorize the films which celebrate its destruction, over the ones which celebrate its triumphs. There’s a moderate exception for films in which some oppressed minority wins a legal (or occasionally physical) battle against the forces of oppression—but even these fare less well with the critics than bleaker fare.
It's a bad argument because one of the people she brings in for criticism is David Denby, and she appears to have entirely missed the basis of his criticism:
And now, the real point: our great musicals were something miraculous. They were a blessed artifice devoted to pleasure, to ease and movement, exultation in the human body, jokes and happy times, the giddiness of high hopes. Even the serious musicals, like “Carousel” and “West Side Story,” had their funny moments. (In fairness, there is comedy in “Les Mis,” in the form of the larcenous innkeepers played by Helena Bonham Carter and Sacha Baron Cohen, but they do the same damn pickpocket joke so many times that they hardly provide relief.) If you want emotion in a musical, please, if you’ve never seen it, catch the George Cukor version of “A Star is Born,” in which Judy Garland (John Lahr agrees with me on this) produces the single greatest moment in film-musical history. Late at night in a club, when she thinks no one is listening (while James Mason lurks in the shadows), she sings the Harold Arlen torch song “The Man That Got Away.” Overwhelming.
Denby's problem isn't that Les Mis is insufficiently dramatic: it's that the excesses of mood make it no fun, which is the point of doing a musical (as opposed to an opera) in the first place. And, Denby goes on to say, if it's opera you want, there are many examples of operas that do not have tonal problems or vagueness of plot. There's no point in defending the mediocre just because it's familiar, if better examples of all the things you're looking for are easily and readily available. (I can imagine a world where Les Mis will do because you can't get your hands on a copy of West Side Story, but that world does not exist in 2013)