I had the same thought, glad you phrased it so succinctly! Surprisingly, a Holocaust-denying white nationalist is not someone you should trust on matters concerning global anthropology.
Didn't he write "no reasonable person doubts that the Holocaust happened" in the blog post you are referring to? That's an....unusual way to deny the Holocaust.
I'm not a huge fan of Scott Adams, because I disagree with his worldview, but I have other hills to die on.
He’s not wrong about this, but he’s just repeating very old “tribal knowledge,” about writing. I’ve been hearing the same advice, since I was a kid. Sometimes, I even follow it.