I took his rules as high level observations of the environment's impact on human evolution. But human experience is much more nuanced like you say. I do remember thinking some of the observations could come across as very blunt.

There is a video on the internet of him trying to shoot an old style gun... pretty funny... needless to say it's not his greatest skill.

Jared Diamond Funny video: https://youtube.com/clip/Ugkxm-OUN3XNSdXmZ_fkXs1zZUQziwjaLZN...