(I am one of the researchers mentioned in the article.)
"Joe, why did you fire Carla?"
"She was late to work every other day and spent all day on her phone"
"HR-bot 5000, why did you fire Carla?"
"Weights indices 59738, 837, and 28836 added to over 0.67, yielding a score of only .85, which is below the firing threshold"
Certainly you could look at the input data and try to convince a jury that her performance wasn't acceptable but you can't prove that is why the AI fired her.
The reason developers got fired is because of clear and well-defined rules... that were never enforced except when the decision to fire them for an arbitrary reason had already been made.
I think HR-bot 5000 would treat employees more equitably by forcing employers to confront the inequity of some HR regulations. The same way self-driving cars "drive weird" because they stop at stop signs and drive the speed limit.
There will be protocols for sensitive areas.
Can't do the same with individual decision making.