Yeah how could someone from an imaginary world be asian or black. That's totally unrealistic.
You have a serious case of whataboutism. As soon as you start bringing up either hypothetical scenarios you have no argument. One wrong doesn't make another wrong fine.
So if Black Panther had a scattering of white and Asian actors playing tribes men and women that would be ok? as It an imaginary world.
The Witcher is set in an alternate eastern European medieval setting.