Increasing the disparity between countries reinforces the argument "conditions in your country are so great, stop talking about your internal income inequality" which is, I think, what the original comment was implying to be the point here.

Looking at the article, it uses the term "international dollars" instead of "PPP adjusted dollars," so I think the original comment just missed that the dollars are actually adjusted.

It makes sense if you read the original comment as a criticism of the article ("whitewash the staggering amount of wealth and power is held by American oligarchs" is, I think, pretty clearly a bad thing to do) which just missed that the dollars in the article were adjusted.

yeah, it sounds like we interpreted "whitewash the staggering amount of wealth and power is held by American oligarchs" in different ways.

I took it as minimizing the disparity between rich and poor countries.

I don't know how to reconcile your interpretation with the idea that someone should feel guilty for having a higher dollar income but the same PPP income as someone else.