This is not the only FJ accident where a bootfull of rudder was applied by a relatively inexperienced pilot.
I believe that BoI took the advice of a psychologist who suggested it was a reflex action when faced with an impending impact.
Now I don't know when Kenny applied the rudder with regard to the impact time, but I wonder if this BoI sought advice, rather than assuming it was a learned response from light aircraft flying?