That's irrelevant. The point of my analogy was to show that the meaning of words changes depending on their tone and context. The fact that people 40 years ago used the word 'retard' to mean 'disabled person' doesn't matter in the case of my use of it, as I'm not actually referring to disabled people.
This is so absolutely simple, and It's funny that I, an autistic person, am having to explain to you, in autist-like detail, why an insult that (if anything) should offend me is actually okay.
Do you also whine at blacks for using 'nigger'? "UHH, BUT DUDE, THAT WORD IS BAD!!"
Intentionally feeling offended all day on behalf of other people must be tiring. Words are just sounds onto which we project meaning. Those meanings change. I'm not harming anyone by saying 'retard'.