Atli is just mad that someone could out do her with logic, but, her being just a kid, that's just how it is. Kande is a philosopher, so, pretty much anything she says, he can counteract and use it against her.
This page quite coolly addresses one of the fundamental questions of philosophy: is it worth it? Is the search for the truth worth disrupting your own existence? Or, in Atli's case, is it worth the uncomfortable displacement of her own ideals about god, to question the world around her and their own existence?