Lasz, it's considered justifiable depending on the nature of their "criminal offense." The more violent the crime, even if no one was hurt, marks the kid for psychological evaluation. After extensive medical and psychological testing, a determination is made as to whether or not the child could benefit from behavior altering medication. Sometimes such medication is mandated by the court, after the kids' psychological analysis has been presented to the judge.
In moderation, such medication can be beneficial. But, what most of these kids need, or rather needed, was a belt laid across their rear ends when they were much younger. Much of their anti-social behavior is simply a tool that they use to get what they want. I've seen them blow up over minor issues one minute, and when they get what they want, they become perfectly calm.
Sure, there are a few psychopaths that no amount of medication or counseling will help. We've had a few of them leave our camp and go out into society and commit murder....sometimes to to gain a rep.
There isn't much medication can do about that.