This kind of "language" tells us little, if anything, about the films or filmmaker, but tells a lot about the writer's impoverished critical vocabulary. "I don't like it... so it's shit!" What banal, totally unegaging language. I don't care what this person thinks, if there's any thought at all involved, which I doubt. This is reactive writing. Self centered writing. Bad writing.
Most of the time, that's probably true (and I'd add "lazy writing" to the roster).I do think, however, that scatological references are sometimes useful shorthand, and even appropriate. Someone who calls a Brett Ratner movie "shit," for example, is expending only slightly less thought than went into making the movie itself. One could write a detailed article about all the ways in which the Ratner film sucked, but if such an article was competent (that it would be very long is a given), one would, by definition, be expending far more thought on bashing the movie than went into making it.
Sometimes, this can be an amusing exercise--I picture Klaus Kinski and Werner Herzog at a picnic table combing through old books in an effort to find arcane profanities for Kinski to hurl at Herzog and his films. Most of the time, it's pointless, because most upbudget Hollywood rubbish--the movies that most merit that treatment--isn't, shall we say, up to Herzog's standards.
The "summer blockbuster" season is well underway, Hollywood besieging us with their annual roster of "tent-pole" movies, a parade of brainless CGI-laden inanity that seems to find no denominator either common enough or low enough. How does one write a thoughtful, intelligent critique of a movie like ARMAGEDDON or THE DAY AFTER TOMORROW or INDEPENDENCE DAY or this year's X-MEN ORIGINS: WOLVERINE? Such films wear their cretinous idiocy and complete lack of value on their sleeves. Their mere existence is an insult to the universe itself, particularly given their budgets (which run into the hundreds of millions of dollars). They're the soulless, putrefying leavings of a system of once-mighty studios who, decades ago, stopped living and became mixed-up zombies. And not in any good way.
And if one doesn't want to waste the energy necessary to detail, about them, deficiencies already patently obvious to anyone with more than a few functioning brain cells, I think it's all right to just call them shit.
 As this suggests, at least some little part of the objection to the use of defecation metaphors is that they're so often so poorly aimed!
 Think about this: 70 years ago, the studio system gave us THE WIZARD OF OZ, Laughton's HUNCHBACK OF NOTRE DAME, GONE WITH THE WIND, GUNGA DIN, STAGECOACH, ONLY ANGELS HAVE WINGS, THE YOUNG MR. LINCOLN--more great movies than can be counted. This year, we're getting a FRIDAY THE 13th remake, X-MEN ORIGINS: WOLVERINE, PAUL BLART: MALL COP, a LAND OF THE LOST rehash, a remake of THE TAKING OF PELHAM 123, YEAR ONE, and TRANSFORMERS: REVENGE OF THE FALLEN. Oh, how the mighty have fallen.
 After all, is the bashing I've just given them here that much different? Some windier prose, some whimsical alliteration, some big words, but, when all is said and done, all I've done is call them shit in a fancier way.