That site is specifically for people who are struggling to manage their finances. I'm not really sold that their reasons for not accepting credit cards make sense (lack of fraud protection is the biggest problem). But it makes some psychological sense. You don't see a lot of AA meetings held in bars.
Also, complaining that the average yokel can't manage their credit is like complaining that users can't deal with a command-line interface. Sure the discipline to learn it would pay off, but most people aren't wired that way. Furthermore the credit system as we have it now is designed, by very talented professionals, to prey on common flaws in the human mammal's ability to assess risk and future obligation.
Everybody has something that they're irrational about. Don't make me ask you how much time you've spent on WoW this month.
Lastly, those of us on this board are probably lucky to have relatively high-paying jobs, even if we were less-than-perfect students or tried startup life for a while. The demand is just that great. But software is a huge anomaly in the North American economy. Wages for most people have been flat, relative to inflation, for decades. And furthermore, the risk of sudden and prolonged drops in income has been much higher since 1970 or so. For hackers that means okay, okay, I'll take the stupid J2EE job. For the average North American worker, it might mean accepting some stupid low wage service job.
Anyway, the point is, most families have been making up the difference with credit cards. They're not living extravagantly and still they're falling behind. See this lecture by Elizabeth Warren, "The Coming Collapse of the Middle Class". (http://www.youtube.com/watch?v=akVL7QY0S8A) that punctures some of the myths with hard stats.