Exactly. You clearly succeeded. Actually, I can say emphatically that you did, having read the novel in question.
Also, to this business of being about nothing, a lot of great stories are, in a sense. Same with films. Are classic romantic comedies like, say, The Lady Eve or It Happened One Night really saying anything deep or profound? Of course not. They are entertainment, and entertainment is not a dirty word.
As it happens, I think The Last Word is about many things, not least a plea for literacy and learning in an increasingly ignorant age, and the importance of the written word at a time of escalating technological advances, but it is packaged in an immensely entertaining way.