Actually what he saying is quite conservative, very much so. Less humans, less government, less mouths to feed, less wars, less money on wars spent, less money spent on rebuilding nations after you destroy them.
omg

Let me take just one "point":
Less government --> conservatives want smaller government so people may make their own choice without a central group of overseers forcing them to do this or that.
It is not: "...remove people from the planet so the government is smaller..." lol
I read his manifesto. Each of his points derived from an
extreme liberal/progressive (circa 1920's) perspective.
The concept of "overpopulation harms the planet", and "introduce birth control to control the population explosion", are both liberal in nature. Look it up.