Yes, I do mean that. I ran the numbers & graphs in a few minutes on Excel and came up with results that matched the article's graphs (right down to the automatic color choices - heh). I also mean that the real-world actual, estimated, and (alleged) ideal distributions are a near-perfect match for the mathematical theory. Ergo, it gives lie the selfish "should" part: we are living the reality of statistics, to wit a near-zero differential of income between one person and the next necessitates a huge fluctuation between the bottom & top wealth holdings.
The "innumeracy" comment comes from the fact that those decrying "unfair!" do not realize that a miniscule (two millionths of one percent is nigh unto zero) linear adjustment of percentages translates to exponential variations when applied across hundreds of millions of people. They're performing an equal linear division of the population (20% increments) and somehow expecting the wealth numbers to come out with a similar "fair" equal division of holdings; realizing that the rich should indeed have more than the poor (hence the semantic difference in terms), they resolve this cognitive dissonance by "allowing" the rich to hold some 3x the wealth of the poor - oblivious to the statistical fact that variations in wealth are a matter of exponential-accumulation percentages, not linear accumulations multipliers.
I don't see how income can slide much more "fairly" (i.e., gradually) from the richest to the poorest than a differential of a vanishingly small three millionths of one percent. To say that somehow it "should" (obvious moral arguments of "it's not yours to distribute" aside) be _one_ millionth of one percent instead is to wage class warfare, a very real and bloody process as history shows, because the dividing lines for the 20% groupings mean the guy at the bottom of the highest bracket is making $0.10 more than the guy at the top of the second-highest bracket, and the guy at the bottom of the second-lowest bracket is making $0.0003 more than the top person in the lowest bracket. Comparing between adjacent individuals, and even across entire brackets, with real numbers should strike most as decidedly fair. Is the 80% division hundreds of times wealthier than the 20% division? and the very top unto billions more than the very bottom? sure - and that's reality, folks: the wealth distribution curve is a natural consequence of miniscule percentages aggregated over hundreds of millions of people, and no amount of "should" and social-reengineering (to wit: "comply or die") can render viable change to a natural, social, statistical phenomenon.
But since many people cannot cope with exponential consequences of uniform miniscule percentages applied across a population of hundreds of millions, we will always be faced with those who cry "unfair!" and insist on forcing their notion of "fair" upon the population. The 20th Century suffered some 100,000,000 dead as a consequence, and the authors of TFA (and, it seems, you (rwl)) want to repeat that toll for want of the 0.000003% more their neighbor makes, when 0.000001% would somehow be OK.