I can't believe people are so shocked. I thought it was common knowledge that's she's been the new Julia Roberts for years. All manners and fake smiles to your face but completely selfish and ruthless behind your back. To me that sense of entitlement is not a surprise at all.
Think its because her and her PR team are good at putting over the 'Americas Sweetheart' image and many people in hollywood are scared to contridict it so the only time you hear anything negative is from Anonomous gossip pieces.
Only person in Hollywood I can ever recall going public of her was Kevin Smith which you can read at http://viewaskew.com/press/psycomic/5.html