Ok. And in what wild world of ethics does this even hint at being justified?
Torture is not punishment. Torture is torture.
I would argue torture is punishment, but punishment is not justice. Strongly recommend "Discipline and Punish" by Michel Foucault as an introduction to how our society operates in regards to social control.
It sucks that they thought that was a good idea. A good hard look should be taken at the environment that led to that.
Also: why not teach them to be better, do you think 13 year olds are incapable of learning?
At 13 years old you cannot decide to have sex, vote, drive, drink and so on, exactly because you are unable to decide or take responsibility.