In previous Sendak books children rebel and learn to cope. It was their growing individualism, learning to be grown ups themselves, and often through 'not nice' events (getting eaten by a lion, being king of the monsters), that parents didn't approve. Parents wanted quiet obedient kids.
Sendak showed children being kids, doing things they "shouldn't do" (but learning and growing from the experience).
This book approaches the growing, rebellious child from the opposite direction.
In this book a child makes a mistake, is punished and frightened to death by his caretaker, and only after he's cowed and submissive again (to the point of wanting never to grow older), is love shown.
Sendak's stories used to celebrate and empower the child.
This book is all about beating them back down.
In a weird way this is an excellent teaching book about child abuse.