ccbatson's definition of slavery is not even accurate. It addresses the taking of a person's property but does not address the limitations on the freedom or liberty of the person. With that definition, not only could you include theft, but taxes as well.
Anyway, there are some cultures where people are selling their daughters into slavery. They might call it an arranged marriage, but it is slavery nonetheless. No moral universal absolutes exist for slavery. Try again.
Even though I have very strong beliefs, I do recognize that morality is subjective.
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