They aren’t complaining about historical accuracy. That’s the motte. The bailey is creating fictional universes where leftist fantasies are a reality via dismissal of cause and effect.

Take OP’s example. Why would a fictional fantasy universe need to have any sexual violence whatsoever? The answer is actually very simple: because the existence of sexual violence on a population level is an inevitable consequence of the simultaneous existence of sexual desire, power imbalance, and free will. From these three prerequisites, non-zero sexual violence is inevitable.

If you want to ignore this simple equation to focus on other ideas within your own fantasy setting, by all means, do so. Rape can exist in your world without you feeling compelled to constantly address it in your storytelling. But if you write your story contending that a certain bad thing doesn’t exist, without also addressing the factors that inevitably create that bad thing, then you are writing a bad story without valid internal logic or coherence.