I believe that was because they got the flare exactly right. Without that the result may have looked like the Turkish 737 at AMS. Well done chaps.
Two factors are involved in such kind of flares: the timing and the available energy. The less you have of the second, the less margin you have for the first. As you said the disbelief most probably contributed in delaying the moment where they ad to admit this would be a deadstick landing. Until the AP disconnection at a very low speed, they probably were probably keeping hope of making a normal ILS. When they finally got the proper situational awareness the speed was already way to low and nose had to be pushed down. Fortunately the plane had just enough height to recover the few knots to neutralize some of the Vz.
I think AMS was a different story, the aircraft made a much more ample flare (it had more energy to do that) leading in a much higher impact attitude at much lower speed. In that case casualties were not caused by the aircraft rate of descent but by its high nose up attitude which led to a violent front part momentum on impact.