I know he was just trying to turn heads with the title, get someone to pick up the book etc, but he could have used the exact same comparison for females- females used to be much stronger on the whole too. But strength is not feminine, so he decided to just call the book "manthropology" and make strength the sole identifier of masculinity. That might sound like me just being a miffed female over the lack of "political correctness", but I think it becomes relevant when this book became a sort of media must-read for a little bit, bringing attention to the concept without portrayed the tongue-in-cheek aspect of the book.
Also, for the "unbiased science", hate to be picky, but this isn't it. Fossil records and DNA are solid, but interpretation isn't. The fact that a female chimp was directly compared to a male athlete just shows how framing works- yes the study may be true, yes it may be identified, but that doesn't mean it should have been interpreted that way. Do female chimps have an entirely different bone composition and ridiculous grip strength? Yes, and that is incomparable to humans. So does finding patterns and evidence while you are actively looking to support a hypothesis- you may see connections and overemphasize the importance of small details that you wouldn't if you hadn't already formed the hypothesis.
If your survival is not dependent on your physical strength, it doesn't become a major player in your life. If it does, however, then it is everything. My grandmother spent over 20 years raising 8 children, and she would shoot a deer every week or so for her family. She couldn't drive and didn't own a car, so she would have to rig up ropes to pull the deer back home, up to 10 kms in a trip. She did this usually with 1-2 babies strapped on her front and back. Upon getting home, she would use leverage to haul the deer up over a branch, so that she could let the blood drain out and butcher it with greater ease. She spent the rest of the day fishing and collecting oysters/muscles/berries/fruits/wild vegetables, with the remaining children who weren't school aged in tow. She is around 95 lbs and just under 5 feet tall. You do what you have to do, and we are still capable of it. I think you (and the author, without specifically implying it) are equating "western" stereotypes with how the world works now- most of the world lives below poverty line and have to perform multiple strenuous physical feats every day to survive. The women perform an enormous number of this tasks, which makes the title "manthropology" just seem insensitive.