Why is that word so bad? It is a word like many others we label too egregious to even spell out or say - "the N word". It is a word that segregates you. Isolates you. Demeans you. Relegates you to a category without an identity. Makes you less a person. Takes away your rights. Makes you fear the person who says it. Takes away your your dignity. Destroys your ego. Allows people to do things to you without your permission.
The history behind the word retarded is nearly as long as nigger. (No, I am not afraid to write the word. To me calling it the N word does nothing to diminish its power.)
Mental retardation has existed for all eternity. (Skip reading this if you hate history.) In 1876, the American Association on Mental Deficiency was formed - in about 1978, deficiency was changed to retardation and in 2007 to intellectual and developmental disability. In 1910, words in common usage were feeble-minded (a generic term), idiot (under 2 in development), imbecile (2-7 years), and moron (7-12). In 1959, new words were adopted - borderline MR (IQ 67-83), mild MR ( 50-66), moderate MR (3-49), severe MR (16-32), and profound MR (under 16). In 1973, borderline MR was eliminated as a label, but mild MR was raised to 70. In schools however, other terms were used - educable (could learn up to grade 4 tasks), trainable (learn self-care only), and untrainable.
It doesn't matter which word you use- they all do the same thing. They classify you in a substandard category of life. They allow unspeakable things to be said and done to you. They allow people to expect less of you than others - not only expect less - but give you less opportunity to have access to what would help you be less like what they say you are.
My son Teddy can't read. At 24 you'd think I'd given up. But periodically I read about some new way to teach, or he expresses anger at not being able to read, and I try again. I expect I will never give up on his learning to read. There are those, even those I love, that think this is a wasted effort. Better to spend time on doing things he can do. But he learns more slowly at a different pace, retardedly if you will, and how am I to know at which point he might have caught up and now is ready to read unless I keep giving him the opportunity to learn? I refuse to accept his being labeled as mentally retarded as meaning he has stopped changing, growing, and learning new things.
The horror for me of the word retarded is the little box it puts you in. For some, too many, a little box you can never escape. For others it is just a shout across the playground, where a person gets plopped into the box until they can worm their way out. But at what cost? Much too high a cost.