You see the message based on a true story at the beginning of the movie.But how accurate the depiction in the movie is compared to the true story,you will only to find out after some research.
Movies don’t do justice to books or put it better to the contents of the books.
For example we can look at movie 21,where MIT students rake in millions while gambling at casinos in Vegas .
The movie was so different from the book that one would wonder is this movie really based on the book that I read ?
Even the author of the book mentioned during one of the interviews that movie 21 was not at all what actually happened in reality.
I understand the goal of the hollywood is to make money and get on top of box office.Thus they have to add glamour,romance and drama.But to what extent can you go and still legally claim the movie is based on a true story.
I believe there should be a requirement for a storyline in a movie to meet certain standards to be able to claim certain things in the credits and titles.
Some movies like 21 are so off that instead of claiming it to be based on a true story it should say inspired from a true story.