Forum:Mirror Force Question

If your opponent has a face up "King Dragun" on the field with other attack position dragons, and you have a face down "Mirror Force", could you use the "Mirror Force"? I was told that "Mirror Force" does not target so it would destroy all the monsters on my opponents side of the field regardless of "King Dragun's" ability to protect dragons from spells and traps because it only protects from cards that target. I got into an argument in a duel over this. Could anyone clarify? Any help would be very appreciated.