

You have to keep in mind that white people are much more shocked when they hear about other white people being treated inhumanely because they actually see white people as human. Even the best intentioned white person won’t tend to have as strong of a reaction to a non-white person being treated inhumanely because of how white supremacy is constantly pushing racist messaging on people since birth, internalizing it in them.
They’d be saying stuff like “imagine if it was your daughter/sister/wife/etc.” but aren’t as likely to jump at that when it’s non-white because white and non-white are treated as two distinct concepts, with one being lesser.
So, I will pull back and say it might be a bit hyperbolic to say there would be a civil war, but there would be a much more intense reaction and some of it probably would get violent.
That said, there are white people who care and are fighting. But on a broad level, we know that white people don’t react as strongly when it’s non-white being victimized and that white people are more apt to side with the authority figures in that situation. Renee Good and Alex Pretti get instilled into people’s consciousness far easier than the non-white people they were trying to protect.

It depends I suppose on how you define “book series”. If human development had somehow skipped capitalism and gone straight to something more like what we’d think of as industrialized socialism, there would probably be less individualized fiction book series written by a single author.
But if we define book series as simply a continuation of storytelling within the same universe, fiction or nonfiction, I don’t see how society would ever not have that. Before writing, a lot of history got passed down orally I’m pretty sure. In order to have an oral history, you would have had to be memorizing and passing down a lot of important stories about what came before. These may not be series in the sense of strictly chronological series of events with a clean beginning and ending, but they are still expansive storytelling, as opposed to one-off one-and-done stories.
If anything, I’m inclined to argue that one-off narratives are the more abnormal thing. That it is more normal in human history for narratives to be about the same “world”, usually a nonfiction one. From a logistical standpoint, even in the context of fiction, this is just easier to do; the main force opposing it is intellectual property rights, but fan fiction sometimes bypasses this anyway and gets away with it because it’s not competing for money / claiming to be official works. Making seemingly “original” works is kind of overblown as valuable and harder than it sounds, and some of the works that are perceived as original were inspired heavily by works that came before them. I can’t remember the details off the top of my head, but I’m pretty sure Star Wars was inspired by movies before it (maybe WWII stuff?). I know some of the music took intentional inspiration from Gustav Holst’s The Planets (and he surely took inspiration from things from his era).
So originality is a bit of a myth, depending on how you look at it.