Most likely, Demand Studios' P.R. people freaked out when Wired inquired.
This story likely took weeks to report and write. A graphic artist probably spent at least a week preparing the chart. Good journalism takes a lot of effort, and so few people realize that.
As someone who has been paid to write and edit news for 30 years, this article was pretty depressing, but I already knew about Demand Studios. And you know what? It looks like they take good care of their writers, at least in the karma department. These seem to be folks who have always wanted to be paid to write but never had the opportunity to get paid for it, enjoy surfing the Web, and can bang out three or four of these articles in a day and have some good walking-around-money.
They seem to be mostly American, but at some point I'm sure the Third World will be recruited to drive the price down even further. Seen what they are paying on Mechanical Turk?