"what would you do with such songs? Ban them from being performed in public?"

I'm not into banning stuff, just suggesting that singers might want to think about their repertoire. There are, as Howard said, many songs that are potentially or actually offensive, and I remember ferocious debates about hunting and whaling songs in the 1980s. I used at that time to sing 'The Weary Whaling Ground', justifying it to myself as a song about the exploitation of the crew, which also included a graphic description of the kill that served as a reminder of the horrors of the trade. Others wanted such songs banned altogether. People will draw lines in different places. I can see a justification for singing 'Sir Hugh' with an appropriate introduction, but I still choose not to. I love the Copper Family and wouldn't condemn them for singing 'Sportsmen Arouse', but that doesn't mean I'd want it in my repertoire. I prefer to sing songs I feel positive about in some way, rather than make the excuse (and you did use to hear this in the old days), 'I don't approve of the sentiments of this song, but it has a great chorus / tune etc.'

In the world we inhabit at the moment, the topic of race is extremely sensitive for very obvious reasons. Personally I think a sensitivity to that should over-ride historical accuracy which, to be honest, the folk revival has never cared too much about anyway.