Why did Jibaku want Sunny to hit them rather than Miss Tate?

Jibaku shouts at Sunny and asks her why she let Miss Tate beat them. She asks Sunny why she did not just hit them. She says that Sunny is so scrawny that any swats from her would not have hurt much. Jibaku thinks that Sunny should have pretended to be weak and hit them gently rather than having the teacher beat them.