That chart disproves your entire stance.
You may be technically correct that the US is "not #1".
But if you actually looked at, and understood that chart,
you'd have noticed that the only country with more inequality than the US is Chile.
The US is #2 on that chart.
The chart is sorted according to the pre-tax numbers, but its the after tax numbers that matter.
Inequality may start out higher in other countries thanks to old (seriously old) money, but thanks to their redistributionist policies, actual inequality is lower, and everyone lives more equality, with better healthcare, working conditions, benefits, standard/quality of living, and overall better access to and representation in the market.
So the point that the chart then makes is that redistribution works.
The chart you provided therefore undercuts your own argument and disproves your point.