Took the dog for a walk and thought some more about it. I imagine the tales/rhymes of horrific detail reflected the realities of the day. The plagues, the war, the poverty. A societal coping mechanism of sorts. Found this article:
https://www.bbc.com/culture/article/20150610-the-dark-side-of-nursery-rhymes
Would not the stories from the deeper past, in part, have served a similar function?