I have just deleted a bunch of tired stuff about the nature of truth in writing. Let me cut to the chase.
It's hard to get published. It's even harder to get your book actually sold once it IS published. Fiction is very difficult to sell. A memoir of a vibrant life is much more interesting to sell--especially to the Oprah crowd. They eat that stuff up.
So when you fictionalise your personal story and call it a "memoir" to boost sales for your book, you are about nine kinds of an ass. When you present your writing as fact you are asking for a bond of trust with the reader. When you break that trust, you are 10 kinds of an ass. Hence Gas Guy, James Frey and everyone else whose dummied up their not-so-personal tale to make a buck.
Lying is wrong.
And trusting junkies is stupid.