We’re not talking theoreticals here we’re talking about behaviour that IRL can cause someones death or serious injury .
If the child has only an abstract idea of what is right or wrong and "doesn’t really understand "that shooting somebody dead shouldn’t be done then that child should not be allowed out in public(or even in private for that matter)without being escorted by an adult 100% of the time until it finally does get to understand this no matter how long it takes.
I dont for one moment seriously believe that this child did not understand what the consequences of their actions would be,we’re not talking about an infant here.
Funnily enough I was a child myself once and I can remember what my views on the consequences of my actions would result in.
I dont believe that I was particulary gifted on this score so no matter how much you bend over backwards to excuse the murderer in this case,child or not,it is still a murderer and is still a danger to the public at large.