That's literally leaving out half of the conversation and missing the entire point of my argument.
Understanding how and why people did things has to be understood in the context of the time it happened. To be frank, children had worked throughout history, up to and including the point that Child Labor Laws were passed.
In fact, The labor conditions in agricultural work were worse than the labor conditions in most other industries.
I don't advocate for child labor, but when you point things out that seem egregious from a modern perspective, you have to understand that it might not have been seen as quite as bad, or even justifiable, at the time it happened.
You also greatly overestimate the amount of children that worked in coal mines.
The free market has imperfections, but when you advocate government as the solution, you have to consider one important thing:
"The government is terrible at everything ever."- Every Libertarian economist ever.