Don't take it up with me, take it up with ck2. That's what his statistic (yummyfajitas and the Walton's have more wealth than the bottom 42%) is measuring.
Actually, while I do see what you are saying, I don't think it's that ridiculous. If they have a house with lots of equity they aren't included in this. If you have a negative net worth you aren't doing that great. If you happen to lose your job (like lots of people have over the last few years) now you are in an even worse situation than the guy with a dollar. Now you have no money, and lots of debt.
Having debt ("able to borrow the cost of a house") does not mean you have a negative net worth. It just means you have debt. Having 30k in credit card debt on the other hand...
Yes, it is, because the person with $1 and no access to credit was just made up for the purpose of convoluting a point about wealth inequality in America.