As I said, if you're serious, you'll read the author's other 30,000 words on the topic for which you demand further information.
Reams of articles mean nothing if his opinions aren't well researched and backed up. The article on the whole seems very un-supported.
"As for the statements about blacks failing the department tests, do you really think PDs keep official stats on "Black candidates who flunked our department aptitude and psychological exams, but who we hired anyway," or are you just blowing smoke?"
If the man cannot back up his charges then he should not make them. While police departments probably do not publish stats of Black officers who failed both the aptitude and the psych tests on their websites, I'm sure records are kept somewhere. (Of course getting the information would probably be next to impossible, but I doubt Mr. Stix has the patience for that).