Ableist? Why does the US always ruin perfectly fine English words (if it's the one I'm thinking of)? In French for example there's no negative connotation for the same word, it's what you use if you're late for something...

There's also a lot of perfectly fine technical uses for the word: https://www.merriam-webster.com/dictionary/retard

I mean, go on any highway in Canada and there will be sections where 'retarder' breaks aren't allowed. Those going to get cancelled?

Edit - also associating people with mental disability with that word was a slang usage in the first place, it was never the primary usage.