The story is heartbreaking: incest, abuse, breakdowns, drugs, poverty, addiction. Hoiser handles this well: "Life isn't fair, and thanks to Oprah we all know it." Her response is spot-on - writing for catharsis is one thing, and writing for readers another.
I've had many people approach me throughout the years and tell me they've started their memoirs. A few have even given me their manuscripts to read. It's awful to say this to them, but people don't care. Unless you're famous or notorious, no one cares.
The un-famous people who've been published all have a slant that works, that makes their story palatable and interesting for readers. That's why James Frey's fictionalized 'memoir' A Million Little Pieces was such a scandal, but that's also why it was a bestseller. He found an angle and exploited it. Some might call that lying, others might call it genius (he's got a three-book deal with HarperCollins worth seven figures). That's also how books mentioned in the post - The Glass Castle, Angela's Ashes, Precious, Running with Scissors - became bestsellers. The stories resonated with readers, but so did the lessons.
An interesting life doesn't necessarily translate into a fascinating book. And writers must always, always think of their readers.