You know that book production takes time right? This book was probably finished and at the printers before D3 was released. Would you really expect them to sit on their book once it's done printing and not post about it just because you're upset about the state of the game? Do you think posting about the book some how slows down the patching cycles?
Get over it - they made a book. They've made dozens of them before. It's got nothing at all to do with the game beyond the fact that they take place in the same universe.