@AirRabbit
I doff my cap to you for a thoughtful, well-reasoned and insightful post.
One thing I remember from the time was a BBC Horizon documentary that stated a significant number of that FO's colleagues on AA's A300 fleet had transferred to Boeing types because they believed whole-heartedly in the "weak tail" scenario. Such actions speak to camaraderie and loyalty and they are no doubt noble, even if the evidence points elsewhere.
But if we are to be rational about things then we must follow the evidence, even if we don't like where it may lead. Heaven knows I've been accused enough times of "defending" or "protecting" Airbus when sticking to the evidence is all I've been doing. At the end of the day, even with the speculation over why the FO may have handled the rudder the way he appeared to, there is no arguing with the fact that the vertical stab did not fail until the forces on it exceeded the load limit by a factor of 2.2 times, exceeding the Ultimate load reserve by a factor of 1.47 times.