You ignore my point that it doesn't mean the same now as it did then, dead horse. You'd probably use the word "black" or "black man" in normal conversation without any sense that it was likely to be seen as insulting or offensive, and you wouldn't use the word "nigger" in the same way - back in the 19th century there wouldn't have been any difference between the two expressions.

There's a difference between a song when it is sung in the context of some kind of dramatic performance, or a lecture, or a re-enactment, and the same song in normal use in a pub or club - in the former cases sticking to the actual words is probably the right thing to do.