In Inheritance, Shapiro learns that her biological father is not the man who raised her, and this causes her entire identity to crumble slightly. However, through the use of writing and storytelling, she is given the opportunity to rewrite and process her identity.
By writing and telling her story to us, she is reframing the story, taking the narrative in her own hands, creating new and absolute truths. While it does not provide complete satsifation, it leads to a more grounded and a better understood sense of self.
This is very human of her! I think that is the reason we journal, it gives us time to process and share out emotions in a safe place, but Shapiro was bold and brave, sharing her story for people to read and to relate to.