Did he mean enjoy in the sense of relieving anger kind of happy or being happy to have caning as an option or a sadistic glee? Anger is something you can be self-vigilant about and try hard to root out and school vigilance is needed to spare students from a sadistic teacher to root them out. He sounds like he is more than happy to have the option to relieve his anger. IMHO he doesn’t sound like he enjoys teaching much.
Is there any requirement that he should?
I love teaching. And I think it’s ideal that a teacher should be one who loves it. But I’m not at all sure I’d love it, if I’d spent my career teaching in one of Australia’s typical garden variety secondary schools. Fortunately, that wasn’t my fate. But it is the fate of the majority of secondary school teachers.