lol - "this guy" doesn't like rigor: that's an awesome lack of googling this guy. These comments seem so enamored by the title that they overlook the content of the article where Healy trips over himself repeatedly stating that he's not arguing against nuance.
The six year completion rate of the 2006 cohort was 95% (http://ucomm.stanford.edu/cds/2012). This rate has been consistent, both over time and at other top schools. Of the 5% that don't complete, it's rare that the student is incapable of completing (aaron swartz, tiger woods, etc). The admissions department will be the first to tell you that they pass on _a lot_ of qualified people. Even though most people believe that they were an 'admissions mistake', I still don't think that 'error' is the right term.