How does McCandless justify his treatment of his parents?

Chris claimed he was searching for the meat of life. Like his mentors Thoreau and Emerson, he wanted to cut himself off from what perviously identified him I don't really think he did anything to make his parents feel better. There was the odd cryptic post card to his sister but that was about it. Check out my GradeSaver link for a little more background,

http://www.gradesaver.com/into-the-wild/q-and-a/why-do-you-think-chris-his-back-on-his-family-do-you-think-hes-justified-doing-so-117999/