Have you read the original memo with the citations intact? Gizmodo published an edited version. I would agree that the memo reads like a series of bigoted conjectures if you read the edited version.
The researchers who study the fields he's referencing agree with most everything he said. Hell, a few of them even gave interviews saying he was about, "90% correct".
He was trying to help, and if Google had taken it to heart instead of getting butthurt, they could have used the useful bits and discarded the inaccuracies.