The Bacchae has been the subject of widely varying interpretations regarding what the play as a whole means, or even indeed whether there is a “moral” to the story.
The extraordinary beauty and passion of the poetic choral descriptions indicate that the author certainly knew what attracted those who followed Dionysus. And the vivid gruesomeness of the punishment of Pentheus suggests that he could also understand those who were troubled by the religion.
At one time the interpretation that prevailed was that the play was an expression of Euripides’ religious devotion, as though after a life of being critical of the Greek gods and their followers, the author finally repented of his cynicism, and wrote a play that honors Dionysus and that carries a dire warning to anyone who doesn’t believe.
Then, at the end of the 19th century the opposite idea began to take hold; it was thought that Euripides was doing with The Bacchae what he had always done, pointing out the inadequacy of the Greek gods and religions.