It doesn’t HAVE to, it just tries to do it more often to make the world feel alien. That’s generally high fantasy moreso than scifi though-- scifi often looks like our world.
His orcs were actually based on racist caricatures of Mongolians, unfortunately. “The Mongol Horde.” Unfortunate, but true.
Yeah but you could easily do it with a villain loosely based on a trickster god. Anansi would even be an antihero.