There are other words that one could use besides "nigger" to refer to black people in a derogatory sense. I'm not going to bother listing them here when a quick perusal of a YouTube comments thread will give you plenty of choices. However, I never really knew those other words until college, where I learned a whole bunch of them from one movie.
Doing the right thing? Sure. Why not.
Which is why I was surprised to hear that, sight unseen, Spike Lee had decided to declare against Quentin Tarantino's Django Unchained. Surely an artist who understood the power of language would want to see how it was used before condemning a movie. Not doing so would make Spike Lee the equivalent of the right wing demagogues who picketed the gallery displaying Serrano's Piss Christ. They wouldn't see it either, as, to them, it was blasphemy.
Leaving aside the questions of mental/spiritual/political purity that Spike's objections might raise, let's talk about why someone might use the word "nigger" in a movie like Django Unchained.
Is it historically accurate? Many people argue that "nigger" was used to refer to black people during the period during which Django takes place, and is, therefore, perfectly acceptable. But, many others might counter, there are plenty of other words that were current during the period. Why not use those, mix it up a little?
This counter argument brings to the fore the reason why Quentin might have chosen to use the word "nigger" over others. It is not, surely, a paucity of imagination or vocabulary. The reason why Tarantino uses that word is because this is not a period piece.
At the risk of pedantry, catharsis can be defined as, "The process of releasing, and thereby providing relief from, strong or repressed emotions." Like Inglorious Basterds, Django takes a horrible story (the Holocaust for Inglorious and the history of people owning other (black) people in the United States in Django) and re-imagines the narrative. This re-imagining provides, not a happy ending, per se, but a cathartic reversal: the wrongs are, if not righted, at least avenged. We identify with the victims and then, with them, take the power back. Hitler is finally given the ass-kicking he so richly deserves; the slave kills, not only the master, but the hateful ones who colluded with the master. These things never happened in the "real" world, at least not in such a satisfying fashion, but through an act of magic (for what else is story telling?) Tarantino allows us to go back and have our revenge.
Many people objected to the humor in Django, as well as the language. How could slavery be presented in a comic context? While certainly not all of Django is humorous (and much of it is deliberately horrifying), parts of it are quite funny. Why?
Humor is, especially in Tarantino's world, another mode of catharsis. Where Mel Brooks famously parodied Hitler to rob him of his power, and used the word "nigger" in Blazing Saddles to point up his parody of racists, Tarantino uses humor as mini-catharsis, to relieve the tension (slightly) as he builds up towards a bigger payoff. Where for Brooks, humor was the point and the weapon, for Tarantino, humor is a dramatic tool, with an eye toward the larger catharsis.
And this brings us back to our original question. Why say "nigger?" Like the stories these movies retell, the word "nigger" is more than just itself. It is an uber-narrative, containing an entire history of injustice and repression in a very tight package. It is the one of the few words that still bear a bit of that old black magic (if you'll forgive the pun), that power to wound. Those other words he could have used instead might have been more period-accurate, but period-accuracy is not what Django is about (as the modern soundtrack should clue us in). The point here, as I said earlier, is catharsis.
Using the word itself is cathartic, in its own way. No other word would do. It's the one word you can't say, and by saying "nigger" upwards of one hundred times, Tarantino goes for that hot, transgressive button right in the amygdala. He simultaneously amps up our adrenaline, getting us, the audience, primed for the explosive payoff, and robs the word of its power over us. That is also the point of the violence, and of the relieving humor. He is working us up so that, when the bad guys get what they so richly fucking deserve, we stand and cheer. He creates that space where we can deal with the feelings of unfairness, and our own conflicted attitudes towards race, in a manner where we participate vicariously in the righting of a wrong.
Tarantino is not just a white guy who likes to say transgressive things (though, let's be honest, he is that too). He's an artist who is using the tools at his disposal in an artful way to potentiate and deliver a specific emotional payoff. People who object to this use, while they have a right to their emotions and perceptions, are missing a big part of what he's doing and why.