There is sexism in The Witcher 3, and that is not a bad thing. In fact, the sexism present in The Witcher 3 may contribute to less actual sexism in the real world.
Firstly, I should clarify. Sexism being present in Witcher 3 does not mean that the game itself is sexist. The setting is one where prejudice and hatred are as abundant as air. It is a grim and hopeless world, so it will obviously depict some unsavory individuals with opinions that we might find crude and repulsive. However, that is all this game is doing: depicting, not endorsing.