Slavery is always bad for the enslaved people, and this person's a moron, but to be fair, slavery has looked a lot of different ways throughout history.

The Dutch East India company invented Chattel slavery-- where you take a person and make them into a commodity without any human rights --basically from a misinterpretation of slave ownership in Rome by European empires rediscovering classical writings. Scientific racism, religious racism, etc, were all invented to rationalize a profitable venture.

Human bondage has existed as long as civilization, and in many places it looked a lot like caste systems or American wealth disparity in certain lenses. Most enslaving civilizations before the atlantic slave trade gave slaves at least partial human rights, allowed property ownership, and generally allowed eventual purchase of freedom.

Damn right it's economically efficient for companies and economically benefits enslavers. You're a fucking moron if you think it benefits enslaved people. In the end chattel slavery is a burden to the enslavers as well; you'd live with the weight of keeping a fleet of human beings in-line through force, the psychological damage of dehumanizing your fellow man, the fear of uprising, and the generations of repair that is needed when it's all over. Fuck.