As I said, the THS takes its commands from the elevator position. Look at Fig.63 of the report. When the THS was moving towards a NU trim the elevator was ALWAYS negative (nose up command). I assumed you had read the report.
However, I think you are using the report in an unintended manner. I believe accident reports are written to inform not to educate.
The autostabiliser commands are in this case relevant only to reinforce the point that one cannot judge the THS movement solely on the basis of stick position.
Of course the THS movement seems counterintuitive, but the THS control system knows nothing of the aircraft's stall state. I repeat, it only reacts to the elevator deflection it sees. In this case the elevator was driven almost entirely by the pilot's command, the contribution from pitch damping being very low as the pitch rates were very low. In normal law of course it would be a different story and the THS would be prevented from further NU movement by the down elevator applied as stall protection.
As Machinbird said in an earlier post, the puzzle is why NU movement was not inhibited in alternate law when stall protection became active.