This is a fallacy. It's not a 1:1 stand-in, but it IS that the language used to describe certain species reflects how certain RW races have likewise been characterized. For example, a race of physically strong, low intelligence, aggressive, lazy, and violent savages can describe any number of D&D races (orcs, goblins, ogres, etc) but it's also been used to describe various human groups (Africans, Indians, Mongols, etc.). That isn't to say orcs are supposed to represent any specific one of these cultures, but they fill the same narrative role as them ("the natives are restless") in the stories.