It's a problem otherwise known as 'plus ça change plus c'est la même chose'. Two recent articles make the point very well. One, by Nancy Fulda at Clarkesworld ("Nothing This Fun Could Be Good For You"), compares current worries over videogame violence with past worries over ballet and the waltz.
Another piece, by Princeton professor Alexander Nehamas ("Plato's pop culture problem, and ours"), also raises the specter of videogame violence and the mass media. It delves farther back into history, noting Plato's disdain for literature in virtually any of its forms, because of its corrupting influence on the citizenry. It both misled them as to what was real and what false, and titillated them with depraved role models.
Although much of the talk nowadays centers around videogames, the new kid on the block, one could just as easily make the same points with scenes from the Bible and the Iliad, not to mention in operas like Berg's Lulu, Shostakovich's Lady Macbeth of Mtsensk (condemned -- perhaps by Stalin himself -- in an anonymous editorial in Pravda), or a score of others.
That said, nowadays most cultural liberals are less concerned with moral prurience in artwork, so long as it's kept to the appropriate age group. But Plato's problem is larger. His real problem is that people are not very good at distinguishing truth from falsehood, particularly when provided a compelling narrative. A beautiful lie is often preferred over an inconvenient or unhappy truth.
Plato was entirely right about that, and his problem encompasses all the fictional arts, as Nehamas points out.
Can anything be done about it?