The problem is that you're looking at it backwards - the words (symbols, essentially) don't create the power structure, the power structure creates the words (or symbols). The roles those symbols take are predetermined by societal structure, even if they are used by individuals in a different manner.
This leads to an important distinction between cracker and the n-word, and how the two are usually viewed both by the utterer and the utteree. The n-word is - rightfully - viewed defensively as an attack on all blacks while cracker is usually viewed as a deeply personal insult, one that stems from a characteristic the recipient has no control over (which is why racialization is an absurdity) but not one that is necessarily directed at every white person who ever lived.