I think there's a "temporal proximity effect" that breaks some comparisons. Singing the antisemitism of "Little Sir Hugh" feels different than reviving some antisemitic Nazi anthem. Perhaps because the latter are part and parcel of horrific events of recent memory. Things evolve. 50 years ago, absolutely no cultural relic of the 3rd Reich would have found much acceptance among "right thinking" people. But, in recent memory I have heard a WW2 U-Boat sailor's song, one that made no antisemitic references, but rather was about the service itself, revived.

I'd wager that Confederate Army civil war songs didn't find many sympathetic hearings north of the Mason-Dixon circa 1900. Now, they're a sub-specialty.

There's 'history' and there's 'recent memory.' The two are distinct.

Then there's words that aren't worth bothering with, because they've changed their meaning, and their very utterance by (certain) performers will shut down many listeners. I mean, white shanty singers can't sing "Hogeye Man" in the original. Though African American hip-hop artists can use the n-word in every other line.

Even "gay" is becoming a problem. I mean, how much time do you want to spend explaining the etymology of a given song to all of the under-30's in an audience?

The value in the historical is understanding how people thought, talked, felt, and reasoned.

And the fact is, that historically there was a good deal of unintended or even well-intentioned racism, sexism, and what-have-you-ism. The fact is, that until several decades ago, who you were in the eyes of others, even of yourself, and your place in society was highly determined by accidents of race, gender, culture, religion, and so on.

If you're nor prepared to deal with that, well maybe traditional music isn't the place for you.

Perhaps you should stick with sensitive new-age urban singer-songwriters.