At the same time, perjoration is real-- names associated with disadvantaged groups take on a derogatory meaning. While it's maybe not your fault that "retard" has moved from a neutral, medical term to an insult, it's not great to call people "retarded" in any context.
A certain amount of this is just necessary to treat other humans beings humanely.
A certain amount of this is just necessary to treat other humans beings humanely.