Where did you get that from? How do WORDS justify physical assault?
When that word has a long history of genocide behind them, um, yeah... they are fighting words.
To be fair, upon review, his brother lied about the use of the slur... and he might face charges, which I am fine with.
But you should familiarize yourself with the FIghting Words Doctrine... It's well established in American Law.
www.law.cornell.edu
.
Fighting words are, as first defined by the Supreme Court (SCOTUS) in
Chaplinsky v New Hampshire, 315 U.S. 568 (1942), words which "by their very utterance, inflict injury or tend to incite an immediate breach of the peace. It has been well observed that such utterances are no essential part of any exposition of ideas, and are of such slight social value as a step to truth that any benefit that may be derived from them is clearly outweighed by the social interest in order and morality."