Earlier quoted context omitted.
> Why is this bad? Because they have more money that they can spend, while you an other human being is almost starving, and maybe can't access to education or healthcare. It's not only a matter of billionnaires. We can wonder if it is fair that we (most of us are middle-class of developed countries) live a life of opulence when others are struggling. It strikes me whenever I travel in less developed countries.
But is inequality the root issue or is poverty the root issue? If everyone in the world could afford 1 yacht, but 1% each had 1,000 yachts, that is mass inequality. But would that bother you?
Land, human labour and political influence are three of the most rivalrous goods, goods where the price goes up as fast (or faster) than the supply of money.
In a world with little poverty but vast inequality, everybody could afford TV's and video games; food would be expensive but affordable. Labour intensive services like education and health care would be unaffordable. Owning or renting a nice place would be unaffordable.
(I am not an economist)