The byline on this article reads "James and the Giant Peach is 50 years old. In the story his parents die a violent death and James escapes abusive relatives. Why was Roald Dahl so dark?"
This is an interesting article that discusses the timeless appeal of Dahl's stories and explains that the darkness in most of his stories may come from Dahl's life experiences. I found it particularly notable that Dahl was thought to have an "ambiguous" relationship with children, and that he wasn't particularly attached to even his own children once they hit adolescence.
I especially like the articles list of "Five Dark Storylines;" two of my favorites, Charlie and the Chocolate Factory and Matilda are listed there. Reading the article and thinking about these stories made me realize that most children do like the books with awful adults and/or awful children - as long as they are properly punished in the end and happiness/goodness rules.
Also, I was unaware that there is a biography about Roald Dahl, titled Storyteller, by Donald Sturrock, which came out in 2010. That might be worth the read, but I wonder if it would change how I feel about the books.