Actually Peloton does cause aggro, but you have to be in combat first for it to do so. You just can't pull a mob with it. I know this because I've ran a dungeon where the tank would walk into a mob, not hit it, I use Peloton on the party and got aggro. Even tested it on regular mobs and pulled aggro. As for the Elementals, if I understand correctly, they aggro off of casting and I guess Peloton is considered a cast.
