Visually horrifying, at least for the audience, but I bet someone had to experience this and live to tell the tale.
If this movie would get a few topic tags, it may be like this: sexual content, child abuse, pedophilia, violence, gore, disturbing images, suggestive themes, etc. But I gotta say, after the 'bad guys' do their thing, they are shown frustrated, miserable, hungry and lustful. They're still depicted as people, not one sided characters who's just doing bad stuff for the hell of it.
A slight discomfort for the eyes is quite more pleasant than the pain, suffering and humiliation most people who had to live with. We all have backstories, no one is crazy from birth, we get it with how we grow.