When you call someone a retard, is it because you think it's true?

I don't call people retards. That's what people call me, ha. I know a few of the people who say this to me genuinely think I have some sort of problem. I get called stuff like this often, so maybe I do have something wrong with me.:S

When I call someone a retard, I mean it in a colloquial sense, not in it's literal, medical or textbook definition.

It's like how people call each other "faggot" when they don't really mean the person is being gay, it's just their dumb way of saying "you're an idiot".

Sometimes we take on words and create meanings for them that deviate from their original definition. I don't say it in offense to people who are cognitively or mentally impaired.

Yes Ive said it even though I try not to use that term its usually because someone is being annoying or acting stupid.
Once my friend got mad because a janitor at McDonalds mopped her foot with a wet mop while we were waiting in line and she said "hey watch out you retard!"...only to realize that person actually WAS in fact retarded(or Downs syndrome maybe). She felt so bad...after that I kind of stopped using the term for sarcastic purposes.

I don't often use the word to describe a person even if appropriate. Although I was recently riding the bus with some animated rudn people. They were yelling at people and the driver almost kicked one of them off because he got into an argument with someone. The sad thing was that he was clearly not a very bright person. Most people ignored him. I don't think he knew his mutterings were out loud. Except one person engaged him and started a shouting match. And she seemed to have killed many brain cells over the course of her life.

I found myself retelling the story to coworkers and the best term I could come up with was "retarded assholes."

I felt a little bad but I really couldn't find a better way to describe those two people.

Uh sometimes, yes.