Can you explain why it's inherently bad people get richer at different rates?
There is kind of a standard comment one hears from the Right that preventing people from getting arbitrarily rich through "income redistribution" is basically taking away the incentive to do good work by the people most capable of doing it. And there is also the suggestion that attempts to change the wealth distribution are, in reality, motivated by jealousy and failure to appreciate some people really are just a lot, lot better
than everyone else.
First of all, when you say something is "good" or "bad", no argument is required to defend it. I can just say that I think that it's bad, because it feels bad, and that's it. The reason to give an argument is maybe to connect it with some universal set of moral principles that a broader set of people would agree with. However, I've always been leery of applying that kind of deductive method to uncover "the good" or "the just". It's like what economists try to do to uncover human value comparisons (e.g. whether a person values A more than B), where they assume transitivity (if the person thinks A is better than B, and B is better than C; then they think A is better than C); and then later discover that humans don't always value things transitively -- the economist Noah Smith has discussed this on Twitter a few times, as I recall. In principle, if a person's values aren't transitive, then there is a value cycle in their "value comparison directed graph" (nodes are objects, and arrows point from lower to higher value) that can be exploited to drain them of $$$; however, that "proof" relies on yet another
false assumption that a person's values are stable
Explaining ones feelings reminds me of psychoanalysis. Maybe Freud is to blame for the over-rationalized values we hear about today.
Nonetheless, one argument for why the inequality is bad, that connects with a broad set of beliefs -- more widely shared than "it's unseemly for anybody to be that rich" -- is that in American society, money buys power. Not just any power, but political power. With more money, you can buy politicians and also buy more ad time -- and, as just about any politician will tell you, those ads do have a powerful effect on whether someone gets elected. Even Bernie Sanders, who got most of his ad money through small donations and used an army of volunteers to get his message out, has remarked about how great the influence of money is on politics.
Now, whether it's fair or not that someone gets more money to spend on luxuries is one thing; but most people (> 50%) would agree that it's bad that you can translate your out-sized wealth into deciding elections -- it feels undemocratic.
(And whether democracy is good or bad, is yet another question. Probably more than 50% of the population view it as "good".)
I could give other arguments, too -- but they would take a long digression into nature and nurture, so I will refrain.