I can't explain why this keeps happening.
Well, if you listen to all the cognoscenti in the umpteen AF447 threads it happens due to the lack of experience hand flying. That's also the position of the FAA and BEA and Boeing and Airbus.
I'm sure that if pilots would just get rid of their automation dependency, turn all the electronics off, and just fly the plane by good old fashioned 20-20 eyesight this type of incident would never ever happen.