"I'm sorry, I forgot you were retarded, my bad." I think it would be unfair to look to apply opinions on the above example to all instances of the word retard. It would be unfair for me to say it is totally meaningless. I've read that swearing can be split into five broad categories: emphatic, cathartic, idiomatic, dysphemistic, and abusive. I think a lot of people will take the above to be abusive, but functionally I only see it as dysphemistic. There is no truth to the statement. He knows that, the victim knows that, and everyone else knows that. It substitutes a lesser word but really causes no more harm, and in that sense I would say it's relatively meaningless. Anyone who takes it as a synecdochial attack on the retarded probably needs to be insulted to add some spice to their life. I do pity him for his boring insults though. It's going to be a tough life with the constant feeling of l'esprit d'escalier if he continues like that. Always remember - think before you speak.