I think if you follow the thread on AF447, you will realise why I am concerned and why it would be advantageous to discuss the root cause.
That's quite a generalization you are making. Don't tar them all on basis of the apparent
non-professional behaviour of a few.
I'm just a lowly PPL but I have been in touch with quite a number of instructors while I was a student pilot and I can tell you that some of them were pretty bad at communicating effectively with the student-pilot both in ground school and while doing air work. Technical proficiency is simply not enough: as an instructor you also have to get the message across (I am a technical trainer by profession). This observation however does not lead me to state that all flight instructors are bad communicators.