"Rock a Bye Your Baby With a Dixie Melody"

I've often wondered why this song--which was also recorded in the studio by the ladies---was included in their act in the early days. Coming to my mind immediately is their Red Skelton Show performance and the popular Copa performance that was released as an album in 1965.

The lyrics, in my opinion, contain phrases which I would have thought would be uncomfortable for them to sing even with the slight changing of some of the original words...
"Just hang my cradle, mammy mine, ---they sing 'mommy'---
right on that masoned, dixen line....
Sing on black joe ---they sing 'sing it slow'---, just as though,
you have me on your knees."

I know this was a popular song by Al Jolsen back around the turn of the 20th century.

Was this a way of 'reaching out' and pampering to the white southern audience at the time?

I will say, they performed this in excellent style. https://www.youtube.com/watch?v=8DDvIQfCI4k