With a descent rate up to ~10000+ fpm, and its attendant airstream howl, STALLWARN is not a good candidate for a conclusion of airframe STALL. They are not consistent, and in fact, the PF remarks re: the "crazy speed", something not generally associated with STALL.
One might assume it was this airmass din that caused all three PILOTS to "miss" the aerodynamic STALL? It is the likeliest of possibilities, imo.
With "good" ROLL control, more evidence still the airframe was "flying".
Further, the ROD could be thought to be indicative of a dive, given these other cues, and eventually, they acted on it too: "Tire, Tire, Tire...."
Captain's suggestion earlier of "Pull" was met with "But I have had Full back for some time..." A defensive statement, to mean perhaps, 'but I have been trying to exit this dive....' (a conjecture) etc.
So in sum, not a complete mystery why the crew didn't believe she was STALLed?
I think far too much is made of the lack of STALL recovery attempts on the way down.
I also believe far too little attention is paid to the reasons the a/c climbed into the STALL. It is this climb that killed her.