Mainly because I know the most accurate account of these men and their story, as presented in the articles at least, might not make it to the movie version. Not that that necessarily says anything one way or another about the quality of the film in its own context, but I don't want my expectations to be biased as to how I think the story will take shape. For instance, in real life, the reporter Downey portrays is still married. In the movie version, he's divorced (presumably from Catherine Keener's character). I give the moviemakers all the right in the world to do this and whatever else they want with their story, but I want to temper what I know about the more honest edition of it all until at least after I've seen the movie.