The theme is child abuse... Except not in the way that you're thinking about it... It's speaking out against it by showing the extreme depiction of it in a controlled art manner.
There are literally thousands of years of texts, debates, classes, hell, entire schools based around those first five words.
You simply cannot use them definitively. It's just not that simple.
There is art that crushes the human spirit. Art about war. Art about slavery. Art about personal trauma. I think if we only depicted pretty war, pretty slavery, pretty rape and genocide, that's pretty disgusting.