If he were just putting it there for the hell of it then there wouldn't be such in-depth examination of the psychological toll the misogyny of the setting takes on his characters. Cersei, for example, would not be even remotely the same person in a world that wasn't so tainted by misogyny. The misogyny of the setting played a major role in shaping her into the person she is. She is far from the only one; the misogyny is a direct influence on the plotline. If it were there and not commented on, then we could assume he was only putting it in to shock readers; but because it is such a major influence on the behaviour of characters, it's safe to assume that he's deliberately putting it in the story to comment on the effects it has.