Dozy, it never seems to have crossed their minds that they were stalled. If you don't think you are stalled, odds are, you won't implement stall recovery. That isn't flying 101, that is understanding pilots 101.
Why they were unable to discern "we are stalled" is hopefully covered, in depth, in the final report. There's been sufficient speculation, to include my own, in these PPRuNe discussions that I'll not add to it.