Here's an article to that might be useful in this discussion. I've linked the whole thing, but I see the relevant section as:
"Adolescents are prone towards increased risk-taking and this is associated with the development of a number of brain-structures Two brain systems are especially important: the prefrontal cortex (PFC), which is the control system; and the ventral striatum, the reward system. The control system is involved in impulse control, the ability to stop a certain urge or action, and thus involved in self-regulation. The ability for self-regulation develops strongly from the age of 12 until the age of 18 [
45], but continues to improve into early adulthood [
7]."
Various international laws and guidelines stress the importance of respecting the developing autonomy of children and involving minors in decision-making regarding treatment and research participation. However, no universal agreement exists as to at ...
www.ncbi.nlm.nih.gov
Society doesn't afford children the same rights as adults to make decisions regarding voting, drinking, medical consent etc. because it doesn't credit them with the same capacity for decision-making as adults. If that principle is established, inconvenient though it may be, it has to apply to sentencing too.
Fully take the point about protecting the public, and they are indeed being locked up. I don't have a problem reviewing the situation in 8 years.
But if a child can't take full responsibility, that suggests someone else is partly responsible. In this type of case, can guardians be prosecuted on the back of their children doing something like this? What about the suppliers of the weapons?