Well, I don't actually want to justify their potrayal - however, it's hardly the first (or 1000th) time this has happened. And it's not just Hollywood. Casting real people as villains is as old writing at least (and probably older). As seen by Salieri (the composer) - the movie Amadeus is based on 200 years old fictional accounts of Mozart's life after all. If people would just stop believing works of fiction, and take them for what they are, this wouldn't be a problem.