I like the idea that he calls this a "conservative" estimate. That sounds much better than "factoid I pulled out of my butt". An unfathomably vast number of papers are published in every mainstream field of academia, STEM and not, every year. The reason we only have "conservative" "estimates" is that nobody can possibly read all of them.
Pick a field and take it down if you can. But trying to build a case against all of social science using the example of someone notoriously elevated despite a lackluster career as a publishing academic doesn't get you anywhere!