J.R.R. Tolkien wrote his books on Middle-earth from a Christian worldview, not necessarily because he wanted everyone to take that from his work, but because that's how he sees the world working. It isn't blatently obvious that The Lord of the Rings has Christian themes, but you don't need to look hard for them. Middle-earth is enjoyable to people for numerous reasons, and the Christian world view isn't necessarily one of them.