It's only dehumanizing and hurtful if you let it be. I don't see, and never have seen the word retarded in a negative context. It was never meant to a derogatory word to describe people with disabilities unlike some other words.
Retarded used to be the term to describe mentally challenged. But people have used the word as a derogatory statement for years now. So it no longer describes the disability, and is used as an insult. When a word is used derogatory it spreads, till its at the point everyone starts using it. So the way the campaign works is if you stop using the word it will not keep spreading. It does make sense.
ANY word used in a derogatory manner is going to offend people. Its not the word, its the intent. And most times its hard to decipher the intent, so the first reaction is to be offended. Obviously some words are easier to decipher than others, but its always the best bet just not to use them at all if you think its going to hurt someone.
Now IMO words are words. If someone is disrespecting you, you know it regardless what the words are.
I always find it funny when people are afraid to say "fat" around me. I've even been told I'm not fat, LMAO. Usually when someone throws something derogatory at me I call them out. I cant tell you how many times I've pulled over in a car, got out and beckoned them after they threw me the finger. Every single time they drove away, LOL.
The way I see it, people using derogatory remarks are cowards, who, in most cases, dont have the balls to back up their statements. Its real easy to call someone mentally disabled a retard from afar. If you cant back up what comes out of your mouth, then you just shouldn't say anything at all.