'Provoke' is an apt word. A performer should recognise that a particular lyric is provocative, and either find an alternative or give a caveat before performing it. It's not as though there is any shortage of material. Not to accept the responsibility for what even one of your audience might feel is at best ignorant, at worst cynical. Saying 'sorry' afterwards doesn't cut it.

I saw Eric Clapton and his pals a year or two ago doing 'Old Black Joe', and wondered about the spectacle of several very comfortably wealthy middle-aged white men choosing to play a song (and I love Jerry Lee Lewis' version) which while not explicitly racist, is the sentimentalisation of the death of a slave. There are thousands of other great songs they could have played without that sour note, of which they appeared ignorant. Would they have played it in front of Barack Obama?

Find an alternative or write your own; if you think dropping 'politically incorrect' material results in folk music becoming bland, find a contemporary political issue to sing about, or just write better.