Isn't that a case of retrofitting a word or phrase how it's viewed and used now (or regarded as politically incorrect so not used) into a time when the word has a completely different context.
Then labelling the person as racist because that's what Hinchcliffe's corner thinks when he reads it, so putting your modern sensibilities upon something.
Least you haven't done what I've seen before though and see someone using black Numeanorians as a way of saying he was racist

.
The sub human thing - which I've never seen those words if they were written by Tolkien, would you not think it was more a description of the behaviour and actions of those essentially corrupted by his worlds version of Satan than somehow trying to morph it into some view about racial superiority?