Why does Krakauer offer a sympathetic portrayal of Chris McCandless?

Many people feel that Krakauer was rather sympathetic if not outright biased towards Chris. In his writing some people find is a certain heroic slant to Chris's story. I think the novel becomes more readable not because of bias but rather that Krakauer understands MCandless. He sees in Chris similar motivations and attitudes as he had as a young man. This gives the book a depth of meaning because Krakauer is a great writer and Chris somehow inhabits parts of Krakauer's belief system. I think Krakauer is critical of Chris when it comes to Chris's treatment of his family. I think, however, that there are the sensibilities of a kindred spirit going on here that gives us a unique access into Chris's world.