What does the r word mean, and why is it bad?

Before, I made a post called "say no to the r word" and I explained the importance to not say that word, but what does it mean to the disability community? Well, once again, we're going to go back to when children with autism were sent away. Back then, it was called "retardedness." A child that was diagnosed a retard were considered useless and incompetent, unable to be raised into working human beings. On October 5, 2010, President Obama signed federal legislation, titled "Rosa’s Law," which replaced a federal law that changed the terms "mental retardation" and "mentally retarded" with the terms "intellectual disability”"and "individual with an intellectual disability" therefore changing the meaning of Autism, but the word "retard" stayed, changing into an insult. The diagnosis for Autism changed into a thing that essentially meant that a person was wired different, meaning that the person diagnosed with an "intellectual disability" was going to act differently and learn differently than other children, but the meaning for "retarded" stayed, meaning incompetent and stupid. Although everyone knows of this word, most don't know that it's a bad word and what it means to the disability community. So many people use this word, and I'm hoping that with this website, people will understand the severity of this word. It's so bad that someone used this world on a child with down syndrome. Please end the use of the r word!