13 year olds should be treated like 13 years olds: they go to school and after they leave they get to go hang out with their boy/girlfriends, do sports, ride their bikes around or play videogames with their friends.
You do realize that has only been the norm for the last 50 years right? And IMO, the last 50 years has been some of the worst.
Mozart at 13 was not hanging out with his friends partying around.
I remember my musical teacher mentioning me about Mozart being over-solicited in his childhood and that that affected his adult life. He died young, after years of health issues.
Newflash: Not all kids are like Mozart
And was that good for him?
The criticism is not of having them work, it is of having them do a specific job, apparently whether they like it or not.