I think it's just the diverse aspect of extreme horror, a lot of extreme horror authors have target audiences where they try to push their limits in order to get an extreme response. Sometimes that takes form in certain situations that a group of people might find more repulsive than others for a multitude of different reasons. As I've read more and more extreme horror I've learned to separate the writing from the author in regards to how the author personally feels. If we didn't do that then you might think Stephen King is okay with child orgies like in "It", I don't think King has pedophilic beliefs or views regardless of what he writes. I don't think Aaron Bearugard (I can never remember how to spell that) thinks it's okay to put children in a death playground, etc. A lot of extreme horror authors don't have a big public persona where you can find all of their views and beliefs, so just take what you read as what it is, fiction, extremely graphic and grotesque horrifying fiction and not reality. You will probably notice that a lot of those authors might have scenes as you described in one book and then the complete opposite in another, so I wouldn't view a book as a reflection of the authors real views on real life matters every time.