I heard the UK version of the book has the good/optimistic ending, the US version omits this and so according to some, the film "enRAB at the wrong point".
I know which episode of The Simpsons you mean, it is "Treehouse of Horror IV", I never made the connection with Alex! 
In the book, Alex rapes 2 10 year old girls
In the film, this is changed to normal sex with teenage girls.