Antiquated or barbaric (amongst others, language is diverse) are words that may express what you’re feeling. Of course, words have multiple meanings and those meanings change over time. Moron was used to describe a deficient intellectual capacity in a medical sense as well, however while an insult, it hasn’t adopted the slur title (maybe it has in some circles idfk). FR clothing is an example where the word is using the same definition as the insult, but describing a physical property instead of an abstract one.
At the end of the day, I usually try to avoid language and actions that are hurtful. With that being said, you can’t satisfy everyone, thus everyone has their own decisions on what values they wish to uphold.
Most of the time, whenever I see folks using the slur, I feel the word “asinine” would work just as well.
Other words that normally fit are: ludicrous, brainless, or downright silly.
Daniel Kish, a man with blindness, uses echolocation to navigate the world and teaches others how to do it. He had done a bit of tv stuff and I think a TED-like talk or two about blindness and perception.
I don’t have any direct quotes, but you may find your answer from him.