He said that a lot of people came to the area trying to relive McCandless' journey. Locals called them "pukers" because they would go into the woods and within a few days of attempting to forage for food, would inevitably eat or drink something contaminated or one of the various mildly poisonous plants in the area, begin vomiting, and give up and return to town (hopefully).
I always thought of McCandless' story as a cautionary tale. I don't think it means we should compromise on our ideals, but I do think it means we need to build skills and awareness. There are causes worth dying for, but most of the time dying can and should be avoided.