Why did Jesus teach in parables?
Why do we tell children fables and fairy tales?
Why do we use terms like cautionary tale, morality tale, allegory?

Because stories help us understand other people.
Stories help us remember things.
Stories open a window to understanding that preaching at people does not.
When you listen to people who either love or hate history, the main difference between them is usually a teacher’s approach. If they had a teacher who emphasized dates and events and IMPORTANT people, they probably don’t enjoy history. If they had a teacher who told them stories about people that REALLY HAPPENED, they probably love it.
In library school, we read a ton of children’s and Young Adult literature and we were required to review it and write those reviews according to a standard of quality. The kiss of death? Didactic writing (i.e. Preachiness)
When you are writing your book, let the story make readers feel emotions. let the story give them empathy. Let the story show them what it is like to be a woman, a person of color, poor, marginalized, underestimated, overestimated, the underdog, the anti-hero, whomever you are writing about.
The lesson comes from understanding what your main character is up against, not through addressing the reader directly and telling them what you want them to think.
