This is not a "metal elitist" reaction. Metallica may have been good for... something or another, but honestly, they were never all that great. And honestly, as far as metal goes, they could have not existed without that huge of a reprecussion.

Iron Maiden, on the other hand, is absolutely irreplaceable. Metal could not have become what it is now without them (and also led zeppelin... and also Megadeth, perhaps... but not metallica. They were just an american version of stuff that was happening in Finland anyway).