I can definitely see both sides on this argument. I think there's an extent of "okay, obviously we don't need to introduce our kids to that sort of thing." And what you describe with that book might fall pretty well into that category.
But with the age of the internet, I tend to take more of a throw up my hands attitude and understand that there's only so much we can keep hidden. If they aren't encountering violence in literature, they'll likely see it on TIkTok or Twitter. And I think it might make more sense for them to be exposed to it in that literary context. I can't remember when my first exposure to violence in books was personally. But what's acceptable violence is also no easy line to draw. Certainly cartoons that I watched early in my childhood depicted what some might call violence, and I don't think I'm any the worse for it. And I read about the brutalities of the holocaust in the book "Night" as early as 6th grade.
Regardless, thanks for submitting! Always enjoy reading your thoughts.