I am talking about people being kidnapped or tricked and then held against their will. People who must work every day long hours or be beat. I am talking about people who are given no money for their labors. People who are bought and sold. The reason is money.
Employees cost money.
It's a lot cheaper to steal their labor than pay them. The surprising thing is that it actually goes on in the United States. In Mauritania, over 100,000 Africans are enslaved. Their families were made slaves by the sword during the 12th century invasions. In the centuries that followed, they accepted it as natural.