Incorrect. You are hand-waving away the difference between discrimination (ugly though it was) and forced labor.
Which is exactly what I said (and therefore not a viable counter-argument).
Again, in each of these situations you offer as defense of the proposition that the American South could have (if allowed to secede) kept a third of its population enslaved for a century-and-a-half past the historical Civil War, you are hand-waving away the problems inherent in obtaining involuntary labor from substantial numbers of people (aka slavery).
Repression and discrimination are not the same thing as slavery. They’re all bad, but they are not the same thing. The Soviet Union’s economy did not feature a third of its population working at gunpoint. North Koreans suffer terrible privations and little liberty, but, again, it is not the case that a third of them work under the guns of the other two thirds.
Yes, repressive governments can and have obtained involuntary labor at gunpoint. And slavery on the small scale certainly exists today, even here in the US (as someone upthread mentioned).
But if you want a 21st century economy that runs on slavery, with a third of the population working under state compulsion—a phenomenon that did exist for a few decades in the American South—then you are going to have to resort to conditions that do not exist.
Think about large-scale slavery as a state policy in this century. The closest you can come to it is, perhaps, the factories that make electronic devices in China. There, the people work long hours for little pay; they may even be locked in. But those factories don’t breed their workers. They have to rely on the fact that the Chinese economy offers so few attractive alternatives, that people are willing to come to the factories and agree to work for such pay as they can get.
Slavery would not work there because it wouldn’t be cost-effective to have someone with a gun standing over each worker. And if you have only one or two or six guys with guns for a room full of workers, the workers will find a way to revolt. If they don’t revolt in the work room, they’ll revolt in the corridors or in the dormitories or in the mess hall or in the exercise yard.
Forced labor at gun-point doesn’t work any better in prisons, and for the same reasons. If you want skilled work done, the prisoner-slaves will sabotage it; if you want unskilled labor, the cost of the guys with guns makes the unskilled labor you obtain cost-ineffective.
Large-scale forced labor at gun-point is simply not economically viable in the 21st century. And none of the examples you’ve offered contradict that fact.