You don't have to like the idea. But you do have to talk to people civilly.
Last I'll say it. 1) The point isn't to play a fantasy game as the Aztecs. The point is to increase the unpredictability and threat of the Mongol invasion. It's not about history. It's about gameplay and replayability. 2) Not everyone is going to like it. So what. That's why DLC works. The people who like it buy it. Those who don't, don't. 3) If you are the type of person who cares more about historicism that's fine. But you don't get to insult people who think a little more outside the box. Don't do it again.