I grew up reading Tolkein and then playing D&D. It seemed to me along with everyone in our playing sphere that D&D was set in Middle Earth, not Medival Times. It wasn't long after the original release when the Gods & Demigods manual was released to help clerics have someone specifically to worship. I never ever thought this game was in any way trying to model reality. Then, of course, you have the various astral and god planes of existence. The only "setting" that makes sense to me for D&D is bringing Middle Earth and myths into a game setting.
How many security breaches have there actually been because of /tmp?