I don't know how many black Frenchmen ran dog sleds delivering mail in the Yukon but I imagine there weren't many.
Political correctness in the year 2020 means that you have to include at least one Negro in every movie, television show, commercial, or anything else that the public will see. The authenticity of the scene being filmed does not matter, as most of the people who pay to watch that stuff have been so brainwashed, that they don't know the truth anyway.