Surprised by conservative theology (BIG SPOILERS)

In the commentary on the DVD, they mention that there was a 2nd fake script written. They filmed at an old church outside Monterey, and thought they would never get permission with the true script. The script they showed to get permission was supposed to be about the history of early settlers in Monterey. However, the final film actually has a very orthodox Catholic theology. I would think the old monks would have liked it.
Succubi lure away those who want earthly glory and physical beauty. Marc overcomes the force of evil with the power of true love. Marc rejects physical seduction, and responds with a defense of marital love. Marc kills the incubus, but is saved because instead of despairing, he returns to the church.
I was surprised that avante garde filmmakers would have such a conservative orthodox script.