Unless it's about the moving forced perspective shot in Bilbo's home, right? That's impressive AF.
I had this same feeling. Same with reading a biography of Kurt Vonnegut. Before reading it, I thought of them in idealistic ways. They had multiple affairs and weren't such great people, even though they both wrote really, really well.
Another type of work I avoid are "the making of ..." documentaries/accounts of classic works of film, music, and TV shows. Pulling back the curtain really destroys the magic.