Yeah, that's a massive problem with the natural language domain all across machine learning.

Unfortunately it's very difficult to track down training data for chess commentary in the first place, let alone trim down biases. For reference, I was able to gather about 1 million samples, but it really needs a billion.

Hopefully through data augmentation and better general intelligence models we can make better progress on bias issues soon, as that's a huge problem when we start trusting AI models too much in life.