Rarity displays her element a lot differently than the other mane six, much less literally, I think. And so she appears not to represent her element much at all. Her desire for high social standings would probably seem awful to most people, and most people probably think it's immoral of Rarity to want that. She just isn't easy to relate to, save for certain cases.
Rainbow Dash, on the other hand, is the sporty, most "masculine" of the group with her love of competition and sports. A vast majority of bronies can relate to this.