It's a short article... I'd say there is a slightly revisionist attitude in the expressed argument, almost fetishist of ethnic diversity, in a solipsistic way. Somehow I assume both Ophelia and Hamlet will be black when staged say in Nigeria... then again, they might very well choose anything but Shakespeare...
The bottom line here is a rejection of normality as a concept. It's normal for a majority group to represent itself. The less represented minorities are less normal, but they are not abnormal. Only if you somehow believe there is no such thing as an average normal - we're all special snowflakes! all perspectives on reality are equally valid! 0_o - then you conflate minority status with unfairness automatically, regardless of objective facts.
Now to finish on criticism, I'm all for the approach of these authors, despite the flimsy historical justification. Cherry picked one might say, but here there is no ethical ground to demand otherwise. The part that seems odd is where lack of diversity is interpreted as a political statement, rather than a reflection of a normal. This is projection by the writer imo, though ill admit it only comes through between the lines. That's the negative aspect of this criticism, it reduces some works to a failed opportunity to explore a specific topic... regardless of the tone.
Come to think of it, in relation to the Witcher, I think these topics of history vs fantasy were explored by Sapkowski himself in a book interview by an historian. The focus was not on ethnic minorities as I recall, but there were many questions about how much or how little the authorial choices were intended to parallel historical organized religion, or historical aspects of germanic-slavic relations. Hmmm the religion stuff was more for the Hussite trilogy I think...
