I think medical terms like retard, mongoloid, idiot, imbecile, moron, insane, cretin, and all other words implying someone is lacking certain cognitive abilities are obsolete. Medical terms will usually include “disability” or “disorder” these days, especially now that we have more knowledge about the underlying causes of someone’s intellectual disabilities.

I don’t think most people object to “idiot” or “dumb” despite their origins in either developmentally disordered people or mute people. It’s actually quite interesting that “idiot” remains much more acceptable than “retarded” when “idiot” was used to refer to people with the lowest IQ scales.

It’s only a matter of time until “developmental disorder” or “special needs” becomes a slur. Every time we invent a new word for someone stupid, people will use it negatively, and the word becomes charged, unless the term is so outdated that people forget it was ever used professionally. It’s an endless game of vocabular musical chairs.