Your "societal factors" explanation is just kicking the can down the road, for societal factors derive from the aggregate of the individuals making up a society. Humans didn't arrive on earth with the social structures you perceive as "sexist" already in place. Humans created these social structures in the civilizations they built, many times over and in isolation from each other. That you can observe that and not notice the common factor - our humanness, our biology - is no different than a religious fanatic able to conclude the earth must indeed be 5,000 years old in light of all evidence to the contrary.
Your assertion that Western society has concluded we want "equality between the sexes" is bizarre. If western society has indeed concluded that, who are all these mysterious sexists I keep hearing about? What you mean is an ignorant and detached elite (of whom Ms Sandberg is undoubtedly a member) have decided there and vision of the good is universal and any resistance (bigots, sexists, etc.) must be destroyed.
Your "examples" as to why the post is "embarassingly bad" consists of one deliberately misinterpreted sentence from a several thousand word review. Bravo.