While child labor is viewed negatively, apparently child labor and child slavery aren’t the same thing, and child labor though it could still be exploitative/cruel in other ways, can be done voluntarily by the child, and with fair treatment/compensation/etc.
I suppose you could make the argument that any child labor opens itself up to problems, but could it be done responsibly? And if not, then at what age do we draw the line of labor being not ok regardless of consent?
Yes, when it’s the product of apprenticeship, where there is a clear gain, without loss in other areas of education. As to the amount of time it takes from childhood, the matter is less clear, as it is within societies that permit cram schools. But if you allow one, then you can allow the other.