Dumbledore you ignorant slut

Finished the Half-Blood Prince about a week ago, and I am still fuming. Didn't everyone see that Snape had never surrendered his allegiance to Cheney...oops...Voldemort. How could Dumbledore have been so naive? Of course there are plenty of other theories, that Dumbledore has a horcrux somewhere, that Snape really is a good guy and only killed Dumbledore because of his oath to protect Malfoy. However I equate Dumbledore's death with Obi Wan's, where the mentor must die so that the hero can rise. And if Rowling writes anything approaching that Dumbledore isn't really dead because Harry has him in his heart, I am going to fly to Scotland and personally deliver a beat-down.