Why do we identify with the protagonist of "To Build a Fire"?

It is especially interesting to note that there is nothing at all likable about the solitary man in Jack London's story, and yet this man engages our sympathy. He is portrayed as brutal, selfish, and not particularly intelligent. He treats his poor dog with cruelty, and toward the end he tries to kill it so he can warm his frozen hands in the dead body. The author gives him an unpleasant appearance with his shaggy beard filled with frozen tobacco juice. And yet we identify with him because he is the only human being in the whole picture. There is a conflict between man and nature, and, being human ourselves, we find ourselves identifying with the man. Furthermore, we are held in his point of view from the beginning until he is dead in the snow. After that we identify briefly with the dog, because now it is a conflict of an animal against nature, and we are closer to the animal than to the blinding-white, ice-cold, forbidding landscape. The story shows that a viewpoint character does not have to have any good qualities, any redeeming features, in order to evoke reader identification. The reader sometimes identifies with a character on the basis of his or her motivation and the problems created by that motivation; and the reader almost always identifies with the character through whose point of view the story is revealed.
It is, of course, significant that the man is all alone in the frozen wilderness. This symbolizes nature's indifference and man's essential loneliness in a godless universe.