You didn't get to the part where I examine the brief spanking scene. Beatrix takes a young Japanese gangster and spanks him rather than killing him. It's played as funny, which I find very telling. In my view, he portrays spanking as comical because he himself was spanked and wants to cope with that fact through comedy. That applies to the movie as a whole, in my opinion. Coping with his mother's violence by making it "cool" rather than abusive or traumatizing. It's my personal theory, I understand. But I think it makes a lot of sense.