And the answer to your question Jennifer Szalai: because Pinker is a weenie and an ass.
I can't wait for the bitching and moaning from the evo-psycho bros over this.
Although maybe my favorite part is when she talks about him whining about how "Better Angels" wasn't treated right:
When he published “The Better Angels of Our Nature” in 2011, he believed he unequivocally showed that modernity and liberal Enlightenment values had made people less violent, and so he was taken aback by skeptical reviews that had the temerity to question his research methods or his conclusions.
“I had thought that a parade of graphs with time on the horizontal axis, body counts or other measures of violence on the vertical, and a line that meandered from the top left to the bottom right would cure audiences” of their delusions and “persuade them that at least in this sphere of well-being the world has made progress,” he recalls near the beginning of “Enlightenment Now.” But Pinker’s inability to “cure audiences” and “persuade them” doesn’t mean he has reconsidered his rhetorical approach; 300 pages after bemoaning those poor souls who read “Better Angels” and weren’t bowled over by his panoply of statistics, Pinker doubles down with still more data. “We have seen six dozen graphs that have vindicated the hope for progress by charting the ways in which the world has been getting better,” he writes.
Pinker fanboys have already been bitching at the author. I saw this amusing exchange: