Not to mention that the genre in which this is so often a problem is fantasy. As in "you created this entire culture and people out of your own fertile imagination and you get to decide what their culture is like". Since when did fantasy have to remain faithful to specific aspects of certain historical cultures? You can draw inspiration from medieval Europe, but your fantasy place is still entirely your own to invent.

I think that part of this boils down to the idea that the weight we place on consent is a more modern concept and that if a society is earlier in development, then there's bound to be a lot of rape. Well, the Code of Ur-Nammu from over four thousand years ago punished rape against a woman with execution. It all varies from place to place. There are a million reasons that an otherwise gritty fantasy culture wouldn't have a lot of rape, and the exercise of figuring out what those are could provide for better depth and world building around the society itself.

That's such a lazy excuse for gritty fantasy writers, though. There are so many ways to portray a world in which the darker aspects of human nature hold sway beyond describing your attractive female characters get sexually assaulted. It's the shallowest and lowest effort way of interpreting "gritty".