I do recognize a degree of courage in a young man going into the wild to heal the angst and alienation plaguing his soul. Yet I bristle at the suggestion such is automatically heroic or independent thinking, and (implicitly or explicitly) the less wounded amongst us can be dismissed as "sheep", as some admirers have done in this discussion.
I am sorry, but I see no evidence that McCandless ever had a single original thought in his head. He never completed the "hero's journey" in either the literary or practical sense -- he failed to achieve enlightenment and return with his boon, to help himself and/or others. He failed. He may have had some courage to admire, but he ultimately failed when it came to the big important stuff.
McCandless was an adolescent in a man's body -- he was not proven capable of handling adult responsibilities. That is not necessarily a negative in itself -- we are where we are in life, and being honest about it and doing something about it is a fine thing. But I am not going to be patient with people lecturing genuine adults about how this adolescent has deep insights into life. Sorry, but that is just wishful thinking by people who mistake ignorance and low intellectual standards for originality.