Why do annemarie and Ellen think kirsti is dumb?

Annemarie and Ellen think Kirsti is "dumb" because she is quite young and often struggles to grasp the seriousness of their situation during the Nazi occupation of Denmark. Her innocent remarks and playful demeanor contrast sharply with the gravity of what is happening around them, leading them to perceive her as naive. Additionally, Kirsti's age and lack of understanding of the dangers they face contribute to their frustration and sense of protectiveness over her.