My take on "trigger warnings" and this article are that it's how we USE trigger warnings not that they exist. The term trigger warning is fairly new but teachers have for years warned students that what they are about to read is graphic in some way but that didn't stop them from assigning it. Trigger warnings started as a way for people who while they are being entertained (trolling the internet for fic to read for pleasure) could avoid things that bother them. Young people today on social media often ask people to put trigger warnings so they can avoid reading stories or accidentally reading about situations that really bother them. This isn't unlike checking out a movies rating & details of the rating before watching.
The problem as I see it is young people pushing this idea that if it bother them therefore they don't need to read/see it into the classroom. I do think it's entirely reasonable for the teacher in the syllabus to a class to mention that some of the books will be of a sensitive nature in one way or another. But that doesn't excuse you from needed to read it. We all grow from reading things that bother us.
Back to the OP's daughter. I have an anxious son myself. DS freaks out by another Charlie & the Chocolate Factory. Doesn't even like looking at the cover of the book or DVD. Had a incident in 2nd grade and still as a High School student it bothers him. Since there is no real reason he NEEDS to read/watch this one particular book we avoid it. As he has grown older he has become a lot less sensitive to things like this.
I think it's very reasonable to pick and choose what is appropriate for an 8 year old. There are many movies for example I wouldn't show an 8 year old because they are too violent. I do think being exposed to things that bother her will eventually help the anxiety. But no need to be extreme about it. Having her learn through history about bad things is probably a good way to expose her.
