Suppose you're put in change of some government and/or legal system, and you need to ban pornography, and see that the ban is implemented. Pornography is the problem, not eroticism. So a lonely lower-class guy wanking off to "Fuck Slaves of the Caribbean XIV" in a Pussycat Theatre is completely off. But a middle-class couple experiencing a delicious frisson when they see a nude version of "Pirates of Penzance" at the Met is perfectly fine - commendable, even.

I have no idea what distinction you're trying to draw here. And I say this as someone who opposes porn but is willing to permit artistic nudes. (I'm not sure what you mean by "erotica" but your example is something I'd probably classify as porn.) I say probably because it's theoretically possible to do it artistically but given the state of the current art world the chances that such a performance be done artistically is low.