so you agree it is a multifaceted word that requires contextual definition in order to be used properly.
The noun retard is recorded from 1788 in the sense “retardation, delay;” from 1970 in the offensive meaning “retarded person,” originally American English, with accent on first syllable. Other words used for “one who is mentally retarded” include retardate (1956, from Latin retardatus), and U.S. newspapers 1950s-60s often used retardee (1950).
so you agree it is a multifaceted word that requires contextual definition in order to be used properly.
https://www.etymonline.com/word/retarded
It’s unfair to judge a word that has over 500 years of use on the last 70 years of history.