Do you mean calling someone with special needs a “retard”? I do not think so. I am not far from that field myself, and you might hear “MR” or MAYBE “retarded”, but I have NEVER heard a professional call someone with differences a RETARD. I don’t believe you.
You don’t believe me but just said yourself MR is used in the Sp. ED. field. That’s the term she used too, MR for mentally retarded and that’s why I mentioned that the term “retarded” was considered rude but she said mentally retarded was common in her field. My point was the use of the term “retarded” by post-grads. It’s acceptable.