Im not really sure how that has anything to do with my comment. You can't dunk on capitalism for child labor and then be like "it's ok if Stalin does it because capitalism does it." That invalidates the original dunk, no?
Children NOT being used for labor is a very recent phenomenon. It has nothing to do with the economic system of the country as the kids of rice farmers in Vietnam are harvesting rice just like the kids of rice farmers in North Carolina, USA are. Children not being used for labor is the results of automation and industrialization.
In the US it was actually the great depression that got a child labor law passed. there had been attempts to get something passed before, even attempts rooted in racism, but it wasn't until everyone was out of work that everyone could agree maybe only adults should be working
Seriously in 3000 BCE millennia before capitalism there were kids laboring.
Edit: capitalism is not responsible for child labor. Child labor has existed for almost all of history until extremely recently and is not inherent to any system