The maker of trash, the barbarian, is less careful to be just.

From John Gardner's Moral Fiction.

To maintain that true art is moral one need not call up theory; one need only think of the fictions that have lasted: The Iliad and The Odyssey; the tragedies of Aeschylus, Sophocles, and Euripides; Virgil's Aeneid; Dante's Commedia; the plays of Shakespeare and Racine; the novels of Tolstoy, Melville, Thomas Mann, James Joyce. Such works - all true works of art - can exert their civilizing influence century after century, long after the cultures that produced them have decayed. Yet it is clearly not true that the morality of art takes care of itself, the good, like gravity, inevitably prevailing. Good art is always in competition with bad, and though the long-run odds for good art are high, since cultures that survive almost by definition take pleasure in the good, even the good in a foreign tongue, the short-term odds are discouraging. The glories of Greece and Rome are now bones on old hills. Civilized virtue, in states or individuals, can easily become too complex for self-defense, can be forced simply to abdicate like those few late Roman emperors not murdered on the street. And like a civilized Roman, the creator of good art - the civilized artist - can easily fall into a position of disadvantage, since he can recognize virtues in the kind of art he prefers not to make, can think up excuses and justifications for even the cheapest pornography - to say nothing of more formidable, more "serious" false art - while the maker of trash, the barbarian, is less careful to be just. It is a fact of life that noble ideas, noble examples of human behavior, can drop out of fashion though they remain as real and applicable as ever - can simply come to be forgotten, plowed under by "progress."

I would not claim that even the worst art should be outlawed, since morality by compulsion is a fool's morality and since, moreover, I agree with Tolstoy that the highest purpose of art is to make people good by choice. But I do think bad art should be revealed for what it is whenever it dares to stick its head up, and I think the arguments for the best kind of art should be mentioned from time to time, because our appreciation of the arts is not wholly instinctive. If it were, our stock of bad books, paintings, and compositions would be somewhat less abundant.