In reading the Hamby verses, I see that I learned a sanitized version of the song. In school in the 1940s we sang verses 1 & 2, along with the chorus, skipped problematic verses 3 & 4 and then came back with verse 5.

sheesh. I have no doubt but that it was deliberate, even though it was in Oregon, not in the American south. We were complicit long before I ever heard the word or concept.