Yes, it's probably better than Nazi Poland. It's still a moral disaster.
Note that while it is true that some kids have committed a crime, there's 2 big remarks to be made there:
1) only <10% have been accused of a crime at all, 90% is there "for their own protection". Doesn't save them from the isolation cells.
2) even for those 10%, they have only been accused. Youth laws do not require any kind of proof. Nor is there defense.
3) The same goes for the 90%, all there is to say the home situation is not safe is the word of one youth worker. This youth worker has never seen the child before the trial, they have only received a single document from another youth worker who is supposed to have seen the child (but often hasn't, in fact that they fail to see those children is often a reason for passing the case to the justice system in the first place: "lack of cooperation")
https://www.youtube.com/watch?v=nzFaNx1Y-fY
(if you set the captions on and to English you should be able to understand)
When I was six years old, I found in an old 'news annual' book a terrible photo from one of the concentration camps. I was upset for days. To this day, I struggle to understand how such intense psychopaths come into power.