I wonder if it has something to do with the fact that reviewers watch a movie with the intention to review it. There might be something in the critical viewing of a narrative that clouds a person instinctive reaction to a film.
Could be. I wonder if there's also a predisposition to regard as a work of genius a movie that the studio insists is a work of genius. There was so much advanced press on how wonderful the English Patient was, long before it was actually seen by reviewers, that critics may have been predisposed to find reasons to like it.