I recently saw "Molly's Game", a pretty entertaining movie that is based on the true story of Molly Bloom, a woman who got into big legal trouble for running high-stakes poker games. After the movie I got into a discussion about the issues it raises, and I realized that I'd rather treat "based on a true story" as 100% fictional. Some might attribute this entirely to concerns about accuracy, and certainly that's a factor. But, honestly, I'd rather not let concerns about factual accuracy get in the way of lessons to be learned from a story. I'm less interested in whether the real-life Bloom pleaded guilty for the reasons given in the movie, and more interested in the dilemmas faced by the character and the reasons why a person faced with the situation shown in the movie might make the choices that they made. I'm less interested in whether real-life Bloom's father did everything that his movie counterpart did, and more interested in the timeless lessons of children and parents and pressures and disappointments.
We don't read great literature because we are interested in the real Scottish king who inspired Macbeth, or the details of life in Dickens-era London. We read it because the slice of life captured has some resonance with us in the present. We don't read the Epic of Gilgamesh in order to learn about Sumer, we read it to learn about people. I doubt that events in space unfolded exactly as shown in Apollo 13, but I can enjoy the characters. "Inherit the Wind" dramatizes a real and important trial, but the oratory raises points that would be of equal importance if the Scopes Trial had never happened.
At best, "inspired by a true story" means that there's a true story that I can go seek out information on if I want, but the movie itself should not be viewed with any goal of learning the story.