I know some will be thrilled; some will be disappointed or puzzled or more. As I write each year as the awards are handed out: trust the process. Remember that the committees (not just the NBA) read tons of books (literally I think if my sagging shelves are any clue). There is much discussion about the books. Ultimately, the hundreds must be narrowed down to 10. Later, the 10 will be further narrowed to 5 and, then, to the winning title. It is not something any committee member takes lightly.
If one of your favorite books is not on the longlist, that does not mean the book is somehow made less. Share that book with others. Hand it off to a kid or a colleague. Sing its praises. There are thousands of books published each year for young people. A very small percentage will be honored with awards. That does not mean you cannot do you own honoring. You should.