I hate to act like a teacher, but these articles are required reading for this episode!
This article details the perhaps anti-racist sentiment that was expressed in an early draft of Charlie and the Chocolate Factory.
This article is more of the same. Same academic, but in an easier, faster to read format.
This blog post (maybe article) is titles Innocence Betrayed. Great read.
This article is written by the same man as the above post, Innocence Betrayed, (Donald Yacovone) and is still a good read.
Some points are reiterated throughout these articles, but I still recommend reading all four.