Looking at the Excel chart, it seems like most people in debt got that from undergrad, not grad school. The data doesn't seem to support their conclusion (that people rack up debt in grad school).
Desire and aptitude don't always go hand-in-hand. The people who always do well (you know the ones) will get the jobs and everyone else will whine about not being able to find a job that pays $100K right out of school. If you're going to end up flipping burgers anyway, why not save 100K and just go directly to the golden arches?