bearfoil,
"The direction of the nose as the a/c impacted is random, undirected, and most definitely not commanded."
Your description of the flight of an aeroplane that has lost
all directional stability is a neat one, and consistent with your hypothesis of the entire fin being lost in flight; unlike the residual stumps of the JAL B747SP, or the B52 in the video link posted by
RR NDB above.
No ambiguity there.
To continue the discussion hypothetically, let me suggest the possibility that
– having read successfully the FDR, under the noses of foreign experts
– the BEA may announce in due course that any recorded sideslip, up to the moment of impact, is not sufficient to be consistent with the absence of the fin, and that the rudder position parameter is available and valid throughout?
In that event, however surprising it might seem, would you accept the validity of the evidence?