Nebula Awards overlook Neil Gaiman's The Graveyard Book

The SFWA has posted the Nebula Award final ballot. I'll post soon on which novels and stories I'll be voting for. It should be noted that many great stories were overlooked this year, which I hope the revision in the Nebula rules will keep from happening from this point on. However, what really irritates is that the Norton award finalists (for best young adult novel) were all selected by judges since they didn't get enough regular nominations--and these professional critics still missed the best young adult novel of the year: Neil Gaiman's The Graveyard Book. Not only is this one of the best young adult fantasy novels of recent years, it also won the fraking Newbery Award. How can it not even make the lists of finalists?