DB might be the most big-name modern antinatalist, but he doesn't speak for the view in its entirety. In fact, I would consider him to be under the cynical misanthrope label for just the reasons you describe.

I am sympathetic to the antinatalist viewpoint but have zero sympathy for malthusianism or eugenics. My sympathy for antinatalism comes more from what Schopenhauer suggests rather than Benetar's bullshit. Ironically, I think there is sort of a logical fork between antinatalism and transhumanism where it is at least extremely difficult to counter the purely antinatalist view without relying on the (to be clear, very real) possibility that we can change what it means to be human on a fundamental level in order to make it better (and yes, this could only be meaningfully accomplished in a socialist society, it would be a eugenic nightmare under capitalism).