@EMIT
No one is saying Boeings can't stall or pilots on other aircraft types can't make dumb decisions. All of your "other accidents" are completely besides the point.
In both AF447 and QZ8501, the left seat pilot tried to apply the correct control inputs and were: 1) unable to do so; 2) unable to understand why; 3) unable to resolve the dual input situation until the end. The AirAsian Captain tried to take over control -- twice -- without success, and he clearly didn't understand what was happening and why.
With linked controls there would not have been ANY ambiguity of what was happening.