It was the thesis of his viral letter[1]. I'm simply supposing that he tried out the same argument in an informal context first, and that's what he's complaining about here.

[1] Yes, it was. Don't pretend that it wasn't. If he genuinely felt that women and minorities were just as valuable candidates why did he write 10 pages about why efforts to ensure their inclusion were hurting google? The fact that he framed the argument creatively doesn't change the fact that fundamentally he feels Google is hiring too many women, thus the diatribe.