This is one of my childhood street songs (Glasgow, Scotland, 1940 - 50). The chorus ran:

"Young folks, old folks, everybody come,
Join the Darkies' Sunday School and make yourself at home.
Buy a stick of chewing gum and sit upon the floor
And we'll tell you bible stories that you never heard before."

... and the verses I remember :-

Now Moses was the leader of a large and mighty flock,
He tried to get some water from the middle of a rock
But when the rock was opened, there rose a mighty cheer,
For, instead of flowing water it was Tennents' Lager Beer!

Esau was a farmer in the wild and woolly west,
His father gave him half the ranch, his brother got the rest.
Esau thought this funny and so very queer
That he swapped the whole caboodle for a whisky and a beer.

While Tennents beer is brewed in Glasgow, 'caboodle' is hardly a Scottish word, and the reference to the wild and woolly west leads me to believe that 'my' version is a street version of the original gospel song, and may have been brought over by American servicemen during WW2.

While I wouldn't use the term 'darkie' now, in those more innocent days it was perfectly acceptable in a society in which 99% of the population were Scots or of Irish descent and the remainder English.
Where we had to be very careful was in our dealings with others who were 'on the other side', ie the great Catholic/Protestant divide - it was almost literally a divide; until I was 12, I knew more Jews than I did Catholics, inasmuch as there was a Jewish girl in my class at school.

I left the city 50 years ago and understand that things are better now.