Bose, I think for the reasons I have tried to set out your assessment may be too sweeping. Yes, we should expect a higher standard of flying from the average CPL if only because he has had to pass a more stringent flight test and endured further training. However, if the mistake arose because of a lack of experience and or training perhaps the instructor is less negligent that if he knowingly set off without an adequate pre-flight brief and without making every effort to maintain situational awareness throughout the flight.
Fuji, by his own admission he let the 'experienced' PPL get on with it. By this very admission he did not take his duty as commander seriously. I made no differentiation between PPL,CPL or ATPL that was other posters. What I did say is that as an Instructor, logging the hours as commander he had a responsibility for the safe conduct of the flight. His standard was below that required of an Instructor and a commander and as such he got into trouble.
I have sympathy with his lack of experience but do not feel that he was treated unjustly. I would however question the chain of command that allowed a naive and inexperienced instructor to get into such a situation.
Regardless of the level of licence that an Instructor rating is attached to that Instructor has to operate to the highest professional standard and understand that being in command is not just about getting hours in the log book it is about ensuring the flight is conducted safely and legally. The Instructor has an obligation to ensure that THEY are competent, qualified and experienced enough to undertake any flight they take on as commander. It is an Instructors duty to set the highest examples of professionalism and airmanship at all times. If they are not experienced enough then they must make this clear to the command chain and gain more experience before they attempt to put themselves into such a situation.