What is your source? Norway, Sweden, and Denmark by all measures have very low income inequality. And you're missing places with really high inequality like Angola, Namibia, and Botswana. They are easy to guess because they are underdeveloped countries that nevertheless have valuable resources (oil, minerals, diamonds) that are exploited by a few elites. https://en.wikipedia.org/wiki/List_of_countries_by_income_equality
The sources has a link above. Your country list is based on GINI however this quizz shows how much percentage the top 10% owns their nation money/assets. it's kinda different a little bit
Then still, which countries have been included? I can't for the life of me imagine that Equatorial Guinea, which has the highest average GDP of Africa yet half the population without clean drinking water would not score above almost all of the above.
Ok, I found it. The full list of countries checked contains 46 countries, so it is rather preposterous to claim these are the countries with the most extreme income inequality. The bottom of this list would probably fall among the low end when we check the whole world.
Here are the 23 countries checked but not included: China, Korea, Taiwan, United Kingdom, Spain, United Arab Emirates, Greece, Austria, Portugal, Ireland, Australia, Belgium, Netherlands, Finland, Italy, Germany, Japan, France, Canada, Mexico, New Zealand, Singapore, Poland
As another point, it would be clearer and more information-full if you reversed the list (Russia is #1, not #23 in most inequality), and added the actual percentages.