Henric didn't know how to answer Professor Dakest. Why they were so intrigued with DADA?...He had no idea why but something about defending one self in times of danger was an important part of being a wizard, wasn't it? He learnt Judo at a young age so he knew that muggles not only used it for self-defence, it was also used to show off their skills in a duel...wasn't it the same thing too for wizards? Anyone could be a dark wizard if she/he had the skills to, and in order to prevent that from happening, we need good wizards to restore the balance.