He does a provide a source in the form of a wikipedia article that uses actual citations [1]. The version with sources (gizmodo removed them in their first publication of the memo), is located at [2].
As for your comment on his "blatant disregard for social context", he explicitly mentions that he believes that biases should be corrected and that society probably also is to blame [3], he just doesn't believe that biological factors does not play any role at all.
Guess people didn't get it. It's not believable to claim to want to correct biases when you want to remove measures that correct biases. Even more ironic is using much of the paper to argue differences between men and women just to say that men are being discriminated against because they aren't treated exactly the same as women. Therefor the program should be replaced by his own version with 4 out of 5 measure focused on women, but despite the differences between men and women doesn't discriminate against men, because he said so. The guy isn't rational, he has just come up with a lot of synonyms for "I disagree".
So he believes in decreasing the false negative rate? I'm confused.