"What you just said is: It's okay to perform a nasty, vile song, if the reviled are not in your audience."

I think that is roughly the opposite of what I said. It's definitely the opposite of what I mean to say.

What I meant was that if anyone has a song to sing which could be seen as being nasty about the Irish, the place to sing it is in front of an Irish audience, and so forth. (There is such a thing as self-disparaging humour, and Finnegan's Wake is an example that I'm happy to sing, in the right comnpany. Pat Murphy probably isn't.)

If the Blarney Brothers sang their song in the midst of an an audience made up of Gypsies, and the audience thought it was a great laugh, I might revise my opinion of it. But I'd advise them to stop singing it until they have tried that. And I'd advise them to think long and hard before they do try that.