Dr D was nurtured and supported by more experienced teachers, and retained. I have no information on Peter Havey, or his school or senior colleagues, but do know feral children can be very destructive.
Teachers are not responsible for kids going bad. They have very prescribed authority for a few hours in a year, years after the childrens character has been formed.
If communities do not support their teachers it will become impossible to attract quality people to teaching. The results will be disastrous and very difficult to retrieve.