why so ?

since i've received the book from a very dear friend, i've recently read james frey's "a million little pieces", the diary of a drug addict fighting his addictions. i pretty much enjoyed frey's style, which was equally fast enough to capture quickly, and tourmenting enough to leave a trace in the mind of the reader.

what i couldn't believe, however, was reading about all the controversies surrounding this book. frey published the book as a memoir book, leading everybody to believe that he was one and the same with the main character of his book. however, at some point, it was revealed that he had augmented some of the incidents in the diary, by describing them at a dimension they never actually had in real life. The public incarceration was taken so far, that in 2006, Frey and publisher Random House, Inc. reached a tentative legal settlement, where readers who felt that they had been defrauded by Frey's "A Million Little Pieces" would be offered a refund.

the reason why i am so puzzled is because whenever reading a memoirs book, i assume that not everything there happened exactly as illustrated in the book, because otherwise it would have seemed more like a newspaper article, than the diary of a person going through a lot. and the reason why i am interested in a memoirs book is because it offers me an insightful perspective of how a certain person perceives his/her life experiences, more than it offers me a very accurate recollection of some episodes in his/her life, which i could maybe access by simply reading a biography written by somebody else. are we supposed to be that offended if a writer inserts some fiction when writing his memoirs ?