Why do you think the trailers they showed have anything to do with the movie?

That was a Landmark Cinema, one of a chain of small art cinemas. All of the movies they showed trailers for are movies that'll be showing at the Landmark in upcoming weeks or months. Didn't you see the posters in the lobby? Few if any of those movies will get any television advertising, or have trailers shown in the big chains, so this is the main advertising they'll get.