The problem is racism, not words. How a word is used and the intention behind it are what makes something a slur, not who said the word. If our goal is to do away with bigotry then everyone should be held to the same standard.
That is not how she was using the phrases. Kasey was just being a silly in-mature teenager.
"I need a slave" Give me a break...that is an obvious attempt at humor. Not that far from someone saying, I need a couple of Hispanic guys to whip my landscaping into shape.