A polite substitute acquires the connotations of the term it replaced, requiring a new substitute.
Pinker's term. "Idiot" was once a clinical grade, as were "moron" and "imbecile". The euphemism cannot outrun the attitude, because the attitude attaches to the referent rather than the word.
In practice
- A form's "disabled" becomes "handicapped" becomes "disabled" again across forty years, and the attitude is the constant.
- A workplace's "personnel" becomes "human resources" becomes "people team", and the function's reputation follows the name each time.