@mekkaokereke What they never point out is, slavery is not only evil, it's also stupid.
The South was so backward they could not maintain their own locomotives post-secession. The high tech industry was all in the North.
They did build a powder mill, by commandeering a Northern-made steam engine to power it!
The cotton picking machine was invented in the 1920s but not used until after WW2, because Black people were still effectively indentured before WW2. They were paid in fake money.