PJ2, please forgive an assinine comment or observation here....
My understanding is that in aircraft pull on the yoke is go up. This was true from day one. The joystick handles the same way.
Now, take that joystick and mount it on a panel that is vertical. Diddle it with your fingertips resting on a sturdy arm rest. If you diddle it up the plane should go up, it's the way people normally think. Translate that "diddle stick" back down to mostly horizontal on the arm rest and you have chaos.
Could the pilot have somehow slipped into a thinking mode that had push is up? That's what the little diddle knob on my Lenovo laptop does. Push to move the cursor up the screen.
Is this a hidden danger in joystick aircraft control? Get too used to a laptop or something and when a crisis hits you revert to laptop thinking and do the wrong thing.
Note that in this case I'd expect PNF to take notice. Somebody noted that the stick inputs are indicated on the displays. So if the appropriate display was on the PNF's scan it should have been noticed.