I think you have to cater to your audience as required. It's called "diplomacy." For instance, I wouldn't necessarily sing an old English folk song which referenced "lily white skin" as a standard of beauty to a diverse American audience. I might alter the lyric. Of course lily white skin back in the days of the song was less about racial superiority than it was about the fact that pale skin was considered symbolic of not having to work outside in the sun, but good luck explaining that to an audience today.

Another example: the following lyric from "The Collier Laddie":

"And would she marry ane that's black
Wi me sae braw and gaudy"

"Black" of course referring to the soot-covered complexion of a miner. But will an audience today understand that? Some might, some might not. Potential for unnecessary controversy, would probably use one of the many versions of the lyric that doesn't use that line.

What about this from "Johnny I Hardly Knew Ye"?

"Ye haven't an arm, ye haven't a leg, hurroo, hurroo
Ye haven't an arm, ye haven't a leg, hurroo, hurroo
Ye haven't an arm, ye haven't a leg
Ye're an armless, boneless, chickenless egg
You'll have to be left with a bowl to beg"

Some might find offensive today?