"Well that was a risk I admittedly took when it came to my lessons. I felt it was best to confront a problem I foresaw. You see many of the Slytherins have been raised in environments where they may have gotten a skewed view of the more illegal aspects of magic and I felt as the teacher of defence if was my duty to protect these children not only from the magic itself but from the ideologies that lead someone down that path. Wouldn't you agree, Headmaster?"