But the TMNT reboot did not get overwhelmingly negative reviews because snooty critics felt it lacked the deep-focus compositions and emotional depth of Orson Welles' legendary debut. No, they gave it overwhelmingly negative reviews because even by the lenient standards of CGI-heavy franchise reboots starring Megan Fox in tight jeans bantering stiffly with disconcertingly realistic-looking beasts, Teenage Mutant Ninja Turtles is poorly conceived. Teenage Mutant Ninja Turtles doesn't need to be compared to timeless art to be found lacking; it's pretty damn awful on its own terms.
Much of a critic's job comes down to contextualization, in placing the film in a specific cultural and historical context. For the TMNT reboot, this might involve analyzing the film within the context of the incongruously gritty comic books that spawned both the film and the previous film and TV series. And above all else, a good critic asks, "What does this film set out to do, and how successful is it in realizing its goals?" They do not ask "Is the Teenage Mutant Ninja Turtles reboot as good as The Godfather?" We're not morons, and we're not insane. Mostly. I hope.
There's no objective truth about a film's quality. Everything is subjective, and when movies are rated on a scale, it reflects that subjectivity. Then people get confused and, in the inevitable tradition of the internet, pissed. When I reviewed movies for The AV Club, for example, Crank 2: High Voltage got a very controversial A-, which led commenters to complain that whenever a film that was supposed to be conventionally "great" got a grade under an A-, that meant we were saying that Crank 2 was better than it. That's not true at all. Crank 2 got an A- because the critic felt it was wholly successful at realizing its ambition to be a crazy, go-for-broke B-movie, not because it deserves to be catapulted into the pantheon of great cinema. Not everything has to be high art, or even remotely artful, even for critics.