Nah folks are immune to Earth element as well. Fire, Water, Earth, Air, Poison, all of the "elements" are immunities / healing for at least 1 enemy in the game, in many cases more. Certainly none of them lack enemies who are resistant to them by any stretch of the imagination.
Fundamentally though "physical damage" cannot be resisted, only dodged or soaked by physical armor. The resistances apply exclusively to magic damage. If you want to ignore resists and immunities, just have everyone focus on physical damage (including from sources such as necromancy).