High morals won't do you much good if you are lying dead in a ditch. If your encounters have no qualms about killing you, what choice do you have but act in a similar way in a critical situation? The only other choice is to die. Maybe much, much later when Rudeus is an OP character, should he ever be, he can afford to ignore lowlifes trying to kill him or those in his company. But that day is still far off.