Many children in some countries are being kidnapped, and forced to work in a harsh place. It’s not only working in a harsh place. They could not get educated. Also, they have no water to drink, no break, and a few sleeping time. Children who work in the mines are having health problems. The use of mercury to separate gold from ore is a particular threat to the children because mercury attacks the brain, kidney damage, blindness, tremors, and speech impediments.
There are laws here and abroad that can encourage countries to do something about it like New Zealand's failed attempt to ban goods made by slaves. I think the argument that it is good for the kids to be slaves is not the case. The choice does not have to be between being a slave or dying on the street from unemployment and poverty. It can be between their parents getting paid a decent wage and child slaves. Companies could still be saving money operating in those countries versus in the West even by paying people more.
Laws are set up against child labour, but inevitably punishments are never harsh. Obviously, as if they were, companies wouldn't use child labour and if they stopped then there's not enough money for the kid in question to get food. Mild punishments are good, but no major ones, because if the punishments get beyond small fines, children will be going hungry.
In America, we don't have this kind of thing. In foreign companies, warlords use force to make those under their sway produce things for large multinational corporations because it's profitable for everyone at the bargaining table.
Also, there is a difference between child labor and slavery. Child labor is paying kids to do work. Slavery is what OP described in her(?) posted opinion argument.
Much of the third-world does not have access to free public education until adulthood like we have in the West. The sad fact is that once companies have pulled out of countries that used child labor, children and teens have been lured into prostitution, drug smuggling, and gangs. Child labor is bad, but the alternatives are worse until these countries are able to provide public education to every child.