It's amazing that a person can be so confidently incorrect like this and not feel any embarrassment. She will still be invited on cable news to share her "expertise."
This is an absurdly idiotic take. If slavery made the US into an economic superpower, then why isn't the south richer than the north?
America experienced its most robust economic growth after the abolition of slavery. Industrialization, manufacturing, railroads, technological innovation, migration from Europe, and free labor markets accelerated the US to the top of the global economic hierarchy.
Slavery arguably stunted the economic growth of the south due to underinvestment in human capital, weaker incentives to invest in education and public infrastructure. Slavery was not only a moral atrocity it was also a terrible economic system which only served to enrich the small wealthy slave-owning class.