That is interesting to know but I feel that Nobel Memorial Prize in Economic Sciences is a bit long and the distinction is not really that meaningful.
Either the research is good or it isn't.
People keep attacking the price simply because it was not sponsored by Nobel himself as if only that direct connection to him transferred some sense of divine truthfulness to the other Nobel prizes that this one lacks.
If you're distinguishing by the type of offense instead of by age, you don't have a youth justice system, you have a minor offense justice system.
Distinguishing by the severity of the offense is already part of the justice system.
Youth justice systems explicitly consider the age and maturity of the offender, not just what they did.
Also I'm not sure why a 15-year-old is a kid in one of your examples and a "kid" in the other.
This is not about tolerating behavior, it's about reforming people to become members of society instead of lifelong burdens for the justice system.
Despite the severity of his action, brandishing kids as "irredeemable" not only throws away their entire future but also burdens everyone else with keeping them contained forever.
That profits nobody.