A primary population that he studies is bonobos and they are profoundly sexual.
Less than half way into the book no final conclusions by me yet, but my impression this far is that he is much of the culture that sees sex as Central to life and he has said that without that how incredibly boring life would be.
Full disclosure, there is no one for whom sex was more Central in their life than me for every moment from the age of about 8 until my late forties. It was an obsession and I understood that to be virtue.
In comparison with my life now, it was so incredibly boring, such an incredible waste of time. Exactly the feelings I have looking back as if I had been a raging alcoholic and looking back at all that wasted life.
Recollections I have of my life before sex, before age 8 or 9, is that there was much wonder and awe and joy in it. It was wonderful.
And for the last 20 years and certainly now that is what characterizes my life.