Have you contacted the game author, Nick Proctor? He is a knowledgeable historian, and there is probably a reason he used that terminology in the game. Usually RTTP games try to be as accurate to the historical setting as they can. This can lead to some antiquated terms being used (but there are limits-- no actual slurs are allowed!), but usually the game book explains why that decision was made. Nick's email is email@example.com
I have used that game, btw. It's a very good tool for teaching about that period!