I question the factual veracity of that claim.
The films are great, no question. But there is only so much depth and detail they can include, compared with the novel. Please read this article as penance for your blasphemy. Then read the book. Frankly, I'm appalled that you haven't.
https://medium.com/illumination/the-lord-of-the-rings-book-versus-film-241ff05ba00d