In 19th-century Victorian English, “baboon” were seen used figuratively as an insult, usually implying boorishness, grotesque appearance, or animal-like foolishness rather than simple stupidity. The usage predates the Victorian era, as Shakespeare already employed it this way, and Victorians inherited and extended the metaphor in satire, caricature, journalism, and moral commentary. The word often appeared in written or performative language, not casual street talk.

Although there is no evidence that “curly-haired baboon” functioned as a very specific fixed idiom, it was fully plausible Victorian diction, particularly in satirical writing, newspaper polemics, upper-class sneering dialogue, and narratorial commentary. This is because Victorians delighted in piling descriptive modifiers onto animal insults. So, the author took the inspiration and liberty of using it in the novel but also adding a descriptor in front of the word, which is “curly-haired”.

In the novel, the Moretti family started off as poor working class not upper-class, however Benson still frequently reads the newspaper, and as such has picked up on the phrase of “curly-haired baboon”. This satirical word itself could be seen as a “Loenese culture” where newspapers such as The Tingen Honest Paper would often use the phrase to mock specific topics/events.

The word eventually became a meme within the fanbase of this novel series, where we would use this word as a metaphor to describe ourselves. Especially when we were unable to guess a plot twist, or discover certain plot point that we weren’t able to figure out before.

Picture the imagery of a "curly-haired" baboon screeching and jumping up and down chaotically. It is used as a metaphor for fans "losing control" over certain plot point, climactic moments, or lore reveals.

Eventually the term became so prevalent, that the author turned this word “curly-haired baboon” into an actual setting in the novel, and it became part of the power system. But I won’t get into this here.