That's sad, and one of Krakauer's most oft referenced failing, though he makes an awesome story out of almost nothing, and his alpine exploits are great reading, and his mentor David Roberts is one of my favorites. The risks involved rarely equal the human cost, but it is done, and where the line is drawn is left to a ton of people to read later, unfortunately or not.
We all take risks, and thank anyone that our lives are our own, and left to interpretation. McCandless very well could have been a modern Muir. His writing and life suggests not, but I don't blame him for trying. Krakauer does not suggest otherwise. Read the book. And tourists be damned.