You hate so much on people that use literally this way, but are do the same thing yourself…

Moron is a term once used in psychology and psychiatry to denote mild intellectual disability. The term was closely tied with the American eugenics movement. Once the term became popularized, it fell out of use by the psychological community, as it was used more commonly as an insult than as a psychological term. It is similar to imbecile and idiot.

Wikipedia