Tolkien and C. W. Lewis (Chronicles of Narnia) were Christians who went church every Sunday.
D&D is fantasy where natural laws are different and even non-sentient creatures can cast spell-life effects. It is not worse than videogames like Warcraft or Diablo III, or comics as "Preacher" or teleserie "Supernatural", "Buffy vampire slayer" or "Charmed". Thor is a superhero by Marvel Comics, and Hercules a Disney hero but I am not going to become neopagan.
However a practicant Christian shouldn't feel too comfortable with the mythology of World of Darkness by White Wolf, worse with "Kult: lost divinity".
The point of view by a Christian is in the reality only there are two sources or origins for supernatural phenomena, Heaven or Hell, without middle term. I know it sounds very radical, but sometimes the middle term is a false fallacy and any things can't always be in the gray zone.
In Spain we were for a time in something like this, in the 90's, where RPGs were almost unknown, before Warcraft of the movies of Lord of the Rings. A man was killed by a fool, and the killed had created something like a storytelling game. It was known like "el crimen del rol" (the role-playing game). This caused a bad image to the "friki" (geek-fanboys) community.
A Christian can read a book about occultism as a child about classic mythology (I am thinking to buy "Atlas of Myths" for my 8y niece in the next Christmas), but he can't believe in the magic as a real cosmic force can be used by mortals without risks.
D&D doesn't promote the occultism but causes the opposite effect: the occultism from real life, without XFs, becomes
boring for geeks and fanboys.