Even though he is being told that Jews aren't good people ,he just doesn't see it that way and because he has shmuel as a friend who happened to be a Jew .People confuse the power of friendship to cross the borders ,that's what
Bruno father as mentioned as to how Jews aren't good people and that they don't deserve to live .Also for that fact that they lost Great War because of the Jews ,that they are doing this for the country own good .