He has no time for book learning or pussy-footing about. He...

He has no time for book learning or pussy-footing about. He wants to show these young men and women what they're up against - evil exists and they better know what they're getting themselves into. He's a one-man initiation ceremony, a walking rite-of-passage. He doesn't believe in treading lightly with Harry or the other students because that won't prepare them for the real world.