Then why must we house them until they are 18?
Sure they understand the law. They also know not to do countless other stupid things that they still do because they are kids.
How many times have we done things that we knew we shouldnt do when we were teenagers?
I am not saying there shouldnt be a punishment of some kind but there is a difference between the ages and that should matter.
No one thinks twice about a 16 year old getting caught shoplifting but a 40 year old doing it raises eyebrows. One we consider a stupid kid and the other we consider a thief.