It's the same category of argument. It also has 'indisputable' statistics supporting it. It does not attack particular persons, just the policy of hiring them. It disparages their co-workers for being born wrong. Much like the manifesto, it's a slam-your-head-into-the-textbook example of racism.

People have also made that exact same argument for decades. Racism was not a moustache-twirling Klanner setting crosses afire (Although it was that, too.) It was the reasoned, fact-supported argument for why people of colour are not as good as Real Americans. Ever since the civil rights movement, it has somewhat fallen out of fashion in the workplace - possibly because most of us accepted the radical notion that the color of your skin has no influence on the quality of your work.