>A 16 year old can waste his or her life by this age if he or she does really badly in school or smokes weed and gets caught.
I agree with the vast majority of your post, but I would say this part isn't super fair. Maybe I'm reading too much into this part, but outside of exceptional cases, we do give minors the chance to recover. I know people who had high school GPAs in the low 2s, that went to community college for 2 years, transferred to a solid university, and have a good career.
At least where I live, your records are sealed at 18 unless you have been tried as an adult (which is exceedingly rare). You can definitely recover from an offense, but it is going to make things harder.
Yes, a 16 year old doing some (alleged) unethical behavior should face some consequences, but no 16 year old should have their life ruined. Intelligence and maturity are not coupled.