Arpad Elo's rating system has no single defined reference pool of players. The way it works is that you take a pool of players, establish the rating that unknow

Arpad Elo's rating system has no single defined reference pool of players. The way it works is that you take a pool of players, establish the rating that unknown new players will receive (1500 in some cases) and then the system evolves from there. There are many disparate pools of players using the Elo system for their ratings, across many games. Just because it was not calibrated with humans does not mean it is not an "Elo" system.