The key takeaway from the article is that the race etc. of the subjects wasn't disclosed to the AI, yet it was able to predict it to 80% while the human experts managed 50% suggesting that there was something else encoded in the imagery that the AI was picking up on.
The AI might just have a better subjective / analytical weight detection criteria. Humans are likely more willing to see what they (or not see what they don't) expect to see.