"confess to being rather bored by all this poring over and implied criticism of the aircraft systems. It seems that one Radio Altimeter failed - so what?"
So it told the a/c it was on the ground, reduced thrust and crashed and killed people.
The point that you seem to be missing is that the failure of a Rad Alt and it's subsequent implications shouldn't have caused this accident.
The RadAlt/AutoThrottle anomaly and subsequent loss of airspeed should not have ended the way it did had
someone been paying attention to what was going on.
That's the point.