I'm on the side of common sense with regards to the David Denby, Scott Rudin ,The Girl With the Dragon Tattoo farce. Which is to say I mainly side with Denby.
If a producer / distributor screens a movie for critics with the hope of winning a critic's award then they are, essentially, asking for a review from all the critics who will then write on their ballot their list of the year's best films. So you should not then be upset when a critic writes an actual review of the film.
Sure, Denby should keep his word however the 'embargo' for expressing an opinion ended the very minute the film was screened for the critics.
Rudin has to know this. But he wants to control the media because he knows that some day he may release a lousy movie that could get killed at the box office if it receives early negative reviews. I am guessing, too, he is upset that the film did not win the New York Critics Circle Award for best film and his only recourse is to call Denby 'immoral' for writing what is, in fact, a positive review.