Loosening any child labor law is a bad idea. Full stop.
But, if you want more…
When I lived in Japan I worked at a Karaoke bar. I did it to practice and learn Japanese, not for the money (which was a fraction of what I was earning teaching English). As a gaijin, I was popular with the patrons who would try to buy me drinks, hit on me, give me their phone numbers, and occasionally slap my ass. I was an adult.
Now imagine a fourteen year old (or 15 - 21 year old) in the same situation.
It sucks for adult waitstaff to be hit on, harassed, and sexually abused at work. I wouldn’t want to visit that on a junior high or high school kid.
