Have you ever considered that these children are victims of organized crime? That they aren't capable of understanding the consequences of what they're doing and that they're being manipulated by adult criminals?
The problem here isn't the lack of long term consequences for kids.
12 year olds know it’s not right to sell crack.
The problem is the gap between lack of legal opportunities for youth and the allure of easy money, status and power from being a criminal. Doesn’t help that the media makes it look so fun and cool to be a gangster.
Just because exceptions are exploitable, doesn't mean we should just scrap all the exceptions. Why not improve the wording and try to work around the exceptions?
The problem that is happening in most Western countries is that criminal organizations take advantage of the fact that minors get reduced sentenced and that their criminal records are usually kept sealed (unless tried as an adult). Whether it be having them steal cars, partake in organized shoplifting operations, muggings, gang activity, drug dealing, etc...
Your reasoning for why this information shouldn't be public record seems to boil down to the fact that you don't agree with other peoples judgement of someone's past crimes. You'd like to see more forgiveness, and you don't think others will show the same forgiveness, so you want to take away all the access to information because of that. To me that seems like a view from a point of moral superiority.
I'd rather people get access to this information and be able to use their own brains to determine whether they want that person working there. If you were involved in shoplifting at 17 years old, and turn 18, I think it would be very fair for a store owner to be able to use that information to judge you when making a hiring decision. To me it doesn't make sense that you turn a magical age of 18 and suddenly your past poor decisions vanish into a void.