[VMG]

> When communicating, there isn't any reason to use a potentially offensive word

Unless you want to offend. You might want to offend to signal the intensity of your rage. Minor range can warrant words like idiotic or stupid, major range calls for words like "fucking retarded git"

> The OP uses the word "retarded" by saying "let's not be retarded". My state of retardation doesn't change from second to second; it's fixed at birth. Insulting what one can't change is the most powerful type of insult. If you call me "stupid", I can always work to be less ignorant. If you call me a "chink" because I'm Chinese, I can't change that, and I feel more insulted.

Unless you really are retarded, he clearly meant that you shouldn't behave like somebody who is mentally disabled, so I don't see the similarity to the word "chink".