The protagonist in Jack London's story is not a likeable man in any way. He seems brutal and unclean. A bad impression is created by the fact that he chews tobacco and has frozen tobacco juice all over his mouth, chin, and the front of his clothes. He is obviously cruel to his dog, and the poor animal fears him and has no affection for him. Nevertheless, this is a story about man against nature, and in any such story the reader will naturally sympathize with the human being, just because he is a fellow human. One of the things the story proves is that a viewpoint character does not have to be good lookiing or kind or good or have any redeeming qualities for readers to identify with him or her. Readers identify with a viewpoiint character on the basis of point of view and that character's problem. We do not have to feel sorry for the man when he dies, but we will probably share his fate in our imaginations. The fact that he brought his own death on himself should not influence our feelings one way or the other. We all make mistakes. We're all human. We all have to die sooner or later.