There is no legal requirement to have a special qualification to teach rock climbing. If, while I am teaching someone to climb rocks, my pupil is killed due to my inability to properly conduct the lessons I would expect to face criminal charges over what would be an unlawful death. If I had represented myself to that pupil as a skilled teacher of rock climbing I would also expect to face fraud charges.
I fail to see (again) why someone would expect to be exempted from any consequences of their actions simply because they are are commercial pilot.
PDR