I might speculate that the appeal is in the more gruesome bits, hypothetically there for the sake of the moral. I see some similar tactics in our own culture where something horrible will be shown "for the sake of showing how horrible it is." The fundamentalist Christian Hell Houses which are put on around Hallowe'en spring to mind. Unless I'm completely misinterpreting, I believe Warren Ellis does a variety of that as well, a sort of moralism by showing immorality. A very popular technique. It panders to the Moral and Immoral alike. Here's William Hogarth's Gin Lane which was made to depict the evils of gin by graphic depiction:
The action of the play is rife with chaos, but there is also sort of a harsh, Darwinian, vendetta morality to the way the events unfold. The action of the play also, largely, takes place onstage aside from the Day of the Locust bit at the end (if you don't get the reference, don't go look it up. Trust me.)
Dionysus is the god of wine and theater. His disciples are frantic, inebriated, violent madwomen. He is my favorite god in the Greek pantheon, probably because the chaos that surrounds him reminds me of observable reality. I feel like the worldview of Greek mythology is one of the darkest and least hopeful around (which is also, partially, why I think it is the most plausible outside of my own religious path.) There are gods and they are not your friends, but don't you dare slight them. If I were to provide a theme throughout the pieces I've read in this collection of Greek tragedy, that would be it. It is one way to answer a seemingly bleak, absurd, and random universe where death, madness, and disease are on the streets around you every day. I can relate.
The show begins, again, with a god coming onstage and delivering the exposition to the audience. Once again, it is also the god who is to afflict the primary character (and, once again, it is difficult to determine a protagonist in the piece.) There is a bone of comedy thrown to the audience in the two old men (or, at least, that's how I would play their scene.) Pentheus comes out and delivers sort of a "you kids get off of my lawn" admonition. His soldiers arrest Dionysus. They lock him up and he levels the palace in a great spectacle that would no doubt usher in the intermission.
Much like our "moralism" mentioned above, Pentheus has a remarkably strong interest in the doings and goings-on at a Bacchanal. It may be my modern sensibilities, but I sense a thick streak of dark comedy through this piece. Dionysus explains why it is necessary for Pentheus to do drag to witness the Bacchae. They tree him and it ends badly for Pentheus. And, for some reason, his mother. And his grandfather now that I think of it. Half of the production budget goes towards stage blood. We come away off our lunch and with a healthy fear of the divine.
Our next piece offers a much lighter view of the gods, Dionysus in particular, as Dr. Eliot, in his infinite wisdom, left a comedy for the end. After this procession of turgid and lachrymose human tragedy, opening the veins of sorrow all over the stage in front of an audience who, presumably, came in to escape their own problems, a comedic respite seems a most welcome apparition of an oasis as we traverse these shifting sands to oblivion. Or, as the wise man said: