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.

He made the exact opposite kind of argument actually.

His argument is let's treat people as individuals and we should stop using inappropriate grouping to push a discriminatory agenda.

An accurate analogy using race might be:

White people are more shy on average than Black people. Companies are using this statistic to justify white only social skills classes.

I think that discriminates against all the black people who are also shy. Let's just make it so any shy person can go to these classes.