The Confederate States of America were onto something: slaves are often necessary for an individual to become rich & powerful. However the War of Northern Aggression a.k.a. the American Civil War was an unnecessary struggle; slaves do not have to be a class of unpaid humans oppressed by collective bigotry. Slavery is not an all-or-nothing category. Plenty of modern individuals are slaves to some degree. Some are wage slaves who can't afford to miss a single day of work, no matter how sick they or their families might be. Some are slaves to their employers, coerced into dressing and behaving in a way that represents their respective companies' values, even when those values clash with their own personal values.
Slaves aren't necessarily people, either. Other animals, computers, robots, and other machines do, dare I say, most of the world's work without any expectation of a fair paycheck.
Modern Americans are quick to condemn our slave-owning ancestors, but we must remember that times have changed. Without a dishwasher, washing machine, air conditioner, computer, etc. etc., I suspect that most of us would desire slaves and that the anti-slave minority would be composed mostly of those who could not afford to feed slaves of their own. Times have changed more than we have, I think.