The original title of Robinson Crusoe is "The Life and Strange Surprizing Adventures of Robinson Crusoe, of York, Mariner: Who lived Eight and Twenty Years, all alone in an un-inhabited Island on the Coast of America, near the Mouth of the Great River of Oroonoque; Having been cast on Shore by Shipwreck, wherein all the Men perished but himself. With An Account how he was at last as strangely deliver'd by Pyrates. Written by Himself."

It's just part of classical literary tradition.

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Huh, now that I think about it, both Robinson Crusoe and light novels spend a lot of time defending slavery...