When Native Americans or Barbary Pirates captured whites as slaves they moved heaven and earth to free them.

Slavery has been around a long time, all over the world, at one time or another it has been practiced by many peoples, including black folks in Africa.
It was considered natural in the ancient world, were slavery was the doom of the losers of war, or part of the plunder taken by legitimate states. Owning a slave not only gave you control of his or her life, it gave you total ownership of their children and descendants forever.

Slaves were used as household laborers, agricultural workers and in businesses and workshops. In the ancient world, some were even given responsible positions as craftsmen, managers and technical consultants. The Athenian democracy of the classic age used them in the silver mines, a particularly bad place to wind up. The slave owners of antiquity felt it perfectly reasonable to own people, but they did not particularly feel their slaves were inferior. They just got unlucky, and every slave owner knew some day, if he was unlucky, it could happen to him too.. But it was the Europeans who perfected the system were slave labor became the foundations of entire industries and economies, on a global scale. And this was in societies which embraced Christianity, which condemned slavery. This is why racism was invented. Modern slavery forced the slavers to assign sub-human status to their victims, reserving them for the most menial labor. Africans were OK for Christians to work to death because they were not "real" human beings. They were just beasts of burden. Capitalism made wide-scale chattel slavery possible, which is not to say there is a causal connection. But it did provide the right conditions for its development. Look up the Triangle Trade.

Nowadays, we don't have slavery per se, but we do have variations, surrogates and substitutes for it, of various degrees, like wage labor. These range from absolute horror to meaningful and productive careers, but essentially they are forms of slavery, although often moderated by various contractual arrangements and salary schemes. But let's face it, if you dread going to work, and feel you cannot quit and do something else, you are a slave.