These data refer to worldwide inequality, while the article speaks to American inequality. The former is significantly skewed by the rural-to-urban migration of India and China as they rapidly modernize.

According to your link, world inequality as a whole is down. This article is about how inequality within a political system (say the USA) affects social stability. Within this context, it matters not whether or not millions of Chinese and Indians have been lifted out of absolute poverty, because those people are not part of our political system.

It's actually a pretty interesting article, you should read it, rather than dismissing it because of your political bias.

Globally, yes.

This article was about the US. Things aren't going in the same direction globally as in first world countries.

Like others have said, this article is strictly about American inequality - as you can see, all the examples given, and all the points discussed, were purely American.

The reduction in global inequality actually relates to the rise in American inequality, as industries that previously drove the growth of the American middle class have off-shored and are now contributing to the growth of the middle class elsewhere.

Stagnant industries that used to be the bread and butter across the US are now major growth factors in China and India.

The article mentions "U.S." nine times and "world" only once in "World War II". I'm confused as to how you could have interpreted it to be about world inequality.