yeah and part of it is they were used as insults but it was more co-opting than anything else. retarded is pretty legit as saying someone is retarded can be proper, but someone will call someone retarded who is not as an insult. then shortening is almost never correct. You might say someone is retarded and that is a correct thing about their condition but saying their a retard is not as its sorta a made up word based on the condition and further tard or tarded is a way to make it more derogatory. Its like homosexual. its a word that means something without being derogatory but to someone who thinks being a homosexual is bad will use it as an insult and using the word homo is almost always an insult (the rare exception is usage among friends to sorta deflate its meaning). When it comes down to it is that folks who spent decades with a word being legitamate will have trouble when it becomes a taboo thing for a decade or so.