Hello ClaireBear, A bunch of red noses, from the nose factory, to you. I think you comment is relevant and an important part of the discussion. I would never expect a singer to avoid any song that might offend or upset me either, but I would personally not sing this song. I wouldn't sing "The Wee Cooper of Fife" either. In fact I'll avoid songs, comic and otherwise, that CONDONE cruel behaviour.
I can think of times when a song, has unexpectedly worked on someone in my audience. I sing "The Picture that is Turned Towards the Wall" and often comment that it's the story of my mother's experience when she turned up pregnant,on her parent's doorstep. A lady once came up to me, after my bracket, and said it was also her sister's story, and she thanked me for singing such a lovely, sensitive song. This song has come to be thought of as a rather over-the-top, slightly comical, piece of Victoriana, but I never present it that way. I sing it as it was intended to be sung and as I feel it. It's not a song that was written with comic intent.
Joy