Should all childrens fiction have happy endings?

First, definitions. Usually I like to have these settled by the end of the first round, so if Pro has any contentions let's try to settle them in the comments section, if we can agree there we can post the settled definition in whoever's argument is next. These definitions are my own but based upon Google's Oxford Languages service.

Fiction: literature or other media that describes imaginary events and people.

Children: a young human being below the age of puberty

Happy ending: A conclusion to a story or piece of media that is a net positive for the protagonist.

Note:This one is harder to define formally as it isn't a word or phrase found in a dictionary. A good edge case to define this would be Harry Potter, where several people he cares about die but the story ending is framed positively and the overarching conflict is resolved favorably. I will also note that it would be a false dichotomy to presume that any story that fails to meet this criterion is an unhappy or "bad" ending. An example of the edge case to me would be Alexander and the Terrible, Horrible, No Good, Very Bad Day. At the end of the story Alexander is still having a terrible day, and it ends with his mother telling him that that's just how some days are. There is no culmination of any plot either negatively or positively, it is just a recording of events.

A. Fables and Folklore

Several modern folktales told today originally had much unhappier endings, and almost all of them have had some dark and gruesome elements removed. For instance, in the first published version of Little Red Riding Hood by Charles Perrault, the girl is devoured by the wolf and no one saves her or the grandmother. Many of Aesop's Fables also end with the death of one or more of the characters, due to their own moral failings.

As far as I can tell, this is mostly because the advent of cinema as a form of storytelling made it more necessary to "clean up" the more grotesque parts. This can be seen as early Disney's first animated film, where the Wicked Queen is falls and dies off-screen, whereas the original story has her put in red hot iron shoes and and forces her to "dance" until she literally drops dead. Other stories, such as Cinderella, even gave their villains redemption arcs in direct to video sequels.

Now, one could argue, why tell a child a story about a girl who gets eaten by a wolf? It borders on traumatizing to a modern audience. However most of these stories taught some kind of important moral. Little Red Riding Hood taught children about the very real danger of straying from the path in the woods, where there actually were wolves, or one could get lost. The girl getting saved at the end undermines the lesson by ignoring the real consequences of such actions.

Though wolves and paths in the woods are much less common in the modern world, the story has remained relevant as it has been reinterpreted to represent the dangers of talking to strangers and especially doing things they tell you to despite your parents' instructions.

TL;DR

Folktales with unhappy endings serve to emphasize the lesson they are trying to teach.

I was going to do a whole second argument about building realistic expectations about failure, disappointment, and the unfairness of life, but I'll save my time 'til my opponent actually commits to the debate.

Sources:

Wikipedia

I will let my arguments from R1 stand.

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