I don't know anyone who reads every book they give their children before buying it, or who buys it then reads it to themselves before reading it to their children - life's too short.
It's reasonable, therefore, to assume that something on sale in the children's section of a mainstream bookshop will be suitable for children, surely? Wyllow that illustration is shocking! I would not have been happy for my children to have a book with that in it, so I'm pleased that someone censored it 20 years before they were born.
Roald Dhal is for quite young children, of an age when parents are likely to want to have an input into what is influencing children. I can't say I worried about mine reading RD, which they did at school, but that doesn't mean that there is nothing wrong with it, and I'm not going to defend it because I didn't pick up on problems at the time, like my own mother used to about Little Black Mambo. She's right that it didn't 'harm' me, but I didn't want my children reading that sort of thing. If this generation of parents don't want their kids reading about someone being 'enormously fat', or tractors being menacingly black-looking', that's fine with me.