What you wrote about "retarded time" is FACINATING. What branch of science is that? So, the term predates the medical terminology "retarded?" I did not know that!
Yes, retarded and spastic are medical terms (outdated) which then turned into insults - spastic is still a kIND of cerebral palsy (which is what I have/tho don't know if it's "spastic.") Then, those words (obviously) became insults because no one wanted to be "like" those people. i.e. have involuntary movement or be "dumb." I don't have an issue with the words themselves as much as the kind of thought they perpetuate in society.
I think Europe is different. But Americans still have the concept that disability makes a person less of a human. Philosophers like Peter Singer have even argued that people with severe disabilities would be better off dead or not born at all. They argue for some kind of litmus test of standard of life, when it actually has never been proved the people with disabilities are "unhappier."
As I was growing uo, I went to mainstream schools. People told me that they never "thought" of me as disabled. In my 30s I had a life change where I realized that CP was part of me. I was fine the way I am. Then, I began making colleagues and friends with disabilities. Now, I work with people with MS, CP, mental disabilities, an amputee, a poet who is death and blind, and many others. I even had to get over some of my own prejudices of disability - which helped by watching my very sexy friend die in the hospital. I am on a quest to know that every one is a valid human and has something to contribute and sometimes I have to look past "the body" and see a person for who they really are.
Obviously, LOL, girlfriends who host sex parties are a little more difficult for me. But I think I will try to use the same technique in that situation