With respect airsupport I don't think you are grasping the difference between cause and blame. Did the pilot cause the accident? Almost certainly! Had he not made those extreme inputs the aircraft would have recovered from the wake turbulence encounter using conventional techniques and the whole incident would be a non-event. Is the pilot to blame? Almost certainly not. He acted in accordance with his training and nothing more should be expected of him. The blame rests largely with AA's training program and to a lesser extent with the rudder feedback design. Your terminology doesn't offend me but it does highlight that you are not familiar with human factors thinking and the distinction between cause and blame in aircraft accidents. It's very noble to try to prevent the pilots being blamed but it's counter-productive to try so hard that you end up hiding the true cause.
Perhaps the stabiliser was weakened by water. The investigators don't think so, and even if it was, it still withstood substantially more than the design loading. If we blame water ingress for the failure above design loading then we could also blame many other things. Perhaps if the weather had been better when the stab was built it would have more strength. Perhaps if the composite fibres had been fractionally thicker the stab would have had more strength. There are a whole load of ifs and buts, but thats not the point. The point is that all aircraft components are designed to a limit, and nobody should ever intentionally take those components outside those limits. Once you exceed that limit all bets are off. If you took every vertical stabiliser on every A300 in the world and tested them to destruction they'd all fail at slightly different levels. Are all but the strongest fins defective because they have failed at lower stress levels? Of course not! Will they all fail above the designated design strength? Almost certainly! If I take a random A300 out and try to break it, is the aircraft to blame if I've got one of the lower failing fins instead of one of the higher failing fins? Hardly! The issue is that any strength above the design strength is a bonus and shouldn't be relied on. Airbus could have quite legitimately designed that assembly to fail at 1% above the design criteria and it would all be quite acceptable. That is why any water ingress in the fin in question is irrelevant. It still failed way above the design criteria. The cause of the accident is that the aircraft was handled in a way that took it outside reasonable operating limits into the realm of structural guesswork.