McCandless was neither so saintly nor so trashy. His diary entries alone make clear he was disturbed in some way.  (This says nothing about his intelligence, which was certainly above average.)  It seems gratuitous to try to pin him with the cabin vandalism.  There's no particular evidence that points at him, and he's not able to defend himself.  

I didn't think Krakauer's book was so bad, but the movie was egregious.  I practically expected the heavens to open and a voice to boom, "This is my beloved son in whom I am well pleased!"