The Devil and the Newfie

The Leafs were a Toronto Ontario team so I'm having a hard time fathoming this joke... unless the leafs were down there in hell, as well. But even then;

Oh think I get it;
I think there used to be a colloquialism that went something like;
It'll be a cold day in hell when the Leafs win a playoff.
But that was around 50 years ago, IDK