It's any type of what we could call the more disturbing side of images. It could just be physical aggression that children are watching.
There were a ton of studies of those images in the eighties and nineties when television was seen as the biggest concern. The more you watch something the more desensitized you get to it, and you start to believe it is the norm.
Looking at those psychological processes, yes, I could very well see that a person's view becomes accepting of this as the norm. Then, they're going to need more and more degrading things to get that same pleasure.