"Based on a true story" is a come-on, the aesthetic equivalent of "no loan request refused." For, at best, the creator has fashioned a film based on his understanding of, interpretation of, and reduction of the report of an actual occurrence.
David MametThe pursuit of Fashion is the attempt of the middle class to co-opt tragedy. In adopting the clothing, speech, and personal habits of those in straitened, dangerous, or pitiful circumstances, the middle class seeks to have what it feels to be the exigent and nonequivocal experiences had by those it emulates.
David Mamet