The footage made me cringe - while I can understand that corporal punishment is more common and accepted in Korea than in some western countries, this went above and beyond disciplining a child, and straight into abuse. Kicking someone where it hurts? Really??!! I'm not anti-corporal punishment, in fact I think it CAN be used effectively, when done the right way (a poster mentioned one of her co-teachers having a huge plastic hammer they use to bop kids, my co-teacher also has one, and it works. It doesn't hurt, it gets their attention, and it's more to express disappointment as opposed to inflicting any kind of physical pain.) What this teacher did was wrong, and she obviously knew it, since according to the Korea Times article, she went to the student's house and apologized to the student's parents.
And being innocent or corrupt in anyone's opinion doesn't rationalize this type of behavior, period.