Using an entire paragraph to simply restate the old saying "If you don't like the US of A, you can just get the hell out" doesn't make the argument any more compelling than it is as a simple sentence.
Some of us would prefer to rather than point at the worst nations and say "Welp, guess we should stop asking questions because at least we don't have it that bad." that we should look at places who appear as if they may be doing better and ask "What are they doing differently from us? And can we emulate any of their policies to improve our own society?"
Looking for new information in order to possibly optimize systems is logical from my perspective.
But if you believe people should not be allowed to ask these questions unless they're first willing to "get the hell out" I suppose that is your prerogative.
That should tell you something about the relative desirability of these lives for most people, even if the dollar amounts are unreliable.
(BTW, the richest people in China and India are very rich, oftentimes richer than their counterparts in the U.S. - the article said that 50% of the occupants of the Boulevard Penthouses were from China. So that's not really a fair comparison. Take a population of 2.5B and compare it with a population of 300M and even if the means of the former are much lower, the outliers are likely to be higher.)