At least part of the problem, in my opinion, is that youth receive basically zero "financial education" in high school.
My girlfriend is 21 years old and just a couple of years out of high school. I can only recall being taught the basics myself: how to make a budget, balance a checkbook, etc. She apparently did not even receive that.
I'm much older than her (37) and, while I'm certainly not "rich" by any means, I'm financially stable and everything I own is completely paid for (ironically, my only remaining debt is my student loans).
She has only recently became interested in the basics of financial matters, such as her credit report and credit score, how loans and credit cards work, etc. Initially, I was amazed at her lack of knowledge in this area. It's not that she's dumb or stupid, she was just never taught anything about finances. She is, fortunately, relatively mature for her age and manages her money well. She has worked since she was first able to and has maintained steady employment and, for some reason, lately acquired an interest in her credit score and increasing it (although it's actually pretty decent for her age).
So we've recently started working on her credit history which, of course, was completely non-existent until she took out a small loan from her credit union for a cheap, used vehicle (with her father as a co-signer) about a year ago. She shops at Victoria's Secret often, so we got her a store credit card from there with a small ($500) credit limit to help her started. I've explained how credit utilization, payment history, etc. factors into her score, so she'll put her purchases (always She completed a vocational program in high school and is already a licensed cosmetologist; we've talked a bit about whether she'll go to college or not (she's already somewhat "behind", in that she didn't go straight to college after high school) but not how it will be funded if she does. If or when that time comes, I'm glad that I'll be around to help her come up with a plan that won't require her to spend the next 20 years paying for it. I can easily see how a typical 18-year-old about to go off to college just blindly signs up for student loans without any true understanding of just what they're committing to financially and without any idea of how long after they complete their education that it will continue to them.
TL;DR: I got kinda sidetracked there for a minute but my point was that today's high school students receive nearly zero financial education or guidance before heading off to college. I am not surprised at all by the facts and figures detailed in this article.