This cartoon is about Mark Twain's "Huckleberry Finn" being censored because it contains the N-word 219 times, and, therefore, is judged to be offensive. The solution to this problem is to replace it with the word slave. However, many argue that Twain uses that particular word to prove a point about Jim's place in society and that censoring it would alter the historical context.
This cartoon makes the point that, if it is truly the N-word that people are protesting, they should consider that young adults are exposed to it outside of books more than in them. Today's music has a tendency to use the N-word more times in a three-minute song than even Twain could have managed. Once censorship begins, there will not be an end. Socially unacceptable words and actions are everywhere. It is up to individuals to decide what they will allow themselves to be exposed to.