Nope. When one uses the word "retarded", they are trying to shame by comparing them to someone who is mentally handicapped. My daughter, who has Down syndrome, is not an insult to be hurled at people as a joke.
Your logic means that this could say, "sometimes your knight in shining armor is just a slow down in tin foul." Your defense of them using the r-word doesn't hold water.
I'm not talking about just anything. I'm talking about a specific word used to hurt and dehumanize those with with mental handicaps. You don't have to agree with me. But now you're informed that those that are disabled do find it hurtful and offensive. And in continuing to use "retarded" in jest, or as an insult, you're knowingly hurting people who cannot defend themselves. It doesn't matter that it doesn't offend you, because your not handicapped. It's about respect, and showing everyone consideration, no matter what makes them different from you.
Your logic means that this could say, "sometimes your knight in shining armor is just a slow down in tin foul." Your defense of them using the r-word doesn't hold water.