The situation globally and the situation in first world countries, particularly the USA, is quite different. Income inequality is falling in places like Brazil, India, and China but is rising in the developed world.
[1]http://en.wikipedia.org/wiki/Income_inequality_in_China
[2]http://en.wikipedia.org/wiki/Income_inequality_in_Brazil
[3]http://timesofindia.indiatimes.com/business/india-business/I...
Things may be getting better in Africa, but they aren't in the US. Since I currently live in the US I'm more concerned about how income inequality is rising here, which is something that his article brushes off as a non-concern simply because I live in a developed nation.
He goes on to argue that I shouldn't worry about how my real wages haven't been increasing because globalization has allowed the wealthy to profit from a bidding war between me and the rest of the world. I'm actually okay with other people being brought up to my standard of living. I'm not okay with people using that as an excuse as to why my own standard of living should be stagnant or declining.
He's arguing that I need to "reframe" my point of view. What that really means is that I shouldn't worry about my own problems, but rather be happy that the rest of the world is improving.
Anyways...
I guess (and there is no real data given in the article), that they just counted for the inequality between countries and found that the lowest incomes in China are doing better against medium or low incomes in other countries.
No wonder, since the medium income for example in Germany has dropped .... and of course the medium incomes in countries like China has risen (but the low incomes in those countries are still "poor" compared to Western standards).