Interestingly, the Mosuo have a different model of the family than most of the rest of humans. In Mosuo culture, men take care of their nieces and nephews, not their sons and daughters. (I had to look this up on Wikipedia to verify it, but I guess it was true based on your description of their sexual relationships - such an arrangement is not stable otherwise.)

So, two points. One, this kind of culture is the exception for humans. I think there are a handful of other cultures that operate this way, but it's still the exception. When an overwhelmingly large percentage of a species behaves in a particular way, we tend to attribute that to instinct rather than random chance - even though there are exceptional cases. I think it's also valid to ask why this kind of culture is not the dominant culture. It's possible that these cultures get out-competed by cultures where men are usually responsible for their own children.

Second, the author did not claim that women don't like sex or have no sex drive. Not enjoying sex was not a part of his argument. His argument was that, in aggregate, men have a stronger sex drive. That claim is consistent with Masuo women having up to 50 partners in their life.