Let's unpack a metaphor: life is a video game. Cause hey, we might be living in a simulation?
In many video games, such as League of Legends (LoL), players control characters (in LoL they are called champions) who each possess unique abilities. Developers strive to make games balanced by making sure no one character is too strong or too weak. In game updates, characters may be buffed (made stronger) or nerfed (made weaker). To each according to their ability, to each according to their need.
The continual buffing, nerfing, and at times total re-working of characters is a cause of both great agitation and interest for gamers.
In games like LoL, the most successful teams are composed of characters whose abilities complement each other. No one character does everything well; a character with very high offensive abilities may be very vulnerable and easy to defeat, for instance. In this way, game developers encourage players to play a variety of characters and use teamwork to compete with each other.
Suppose winning some game gives you one point, and losing that same game costs you one point. If we add up all the points for all the players of this game for a day, we will find our sum to be... zero.
This is a zero-sum game. One player winning entails another player losing.
Supposing that life works like a game of LoL, we see that at times people have differing abilities. As a society, we need regular patch (policy) updates to correct for imbalances. Some groups of people have been taking on a disproportionately high number of losses, while others have continued winning at the expense of others.
Governments by the people and for the people are benevolent game developers. Selfish players that excel at playing particular characters do not want the game of life to be rebalanced because that means they will be nerfed, and statistically, this will probably mean they will end up losing more. Most people like winning and unsurprisingly, dislike losing.
Game developers can set up the rules of their creations in any way they say see fit, only limited by their abilities, available technologies, etc. We are not gods, so we cannot so easily re-program or "patch" humanity.
This may sound dismal. Maybe technology will come along some day that makes life more game-like and "hackable"...
In the mean time, let us recognize that...
One person that produces value does not necessarily take value away from someone else. Taking a win means making somebody else lose in chess; is this the same case for producing an elegant sculpture? Writing some useful software?
Inequality does not entail "winner take all" scenarios. Bach composing beautiful music hundreds of years ago is win for everyone that continues to enjoy it.
I think that becoming comfortable with inequality is essential for happy and ethical living not only because the inequality of people (in terms of the abilities they possess and the value they can produce) is a human fact but because we can expect automation to produce more and more economic inequality in the future [1]. There is, and always will be, someone or something better at any given task [2].
Being comfortable with inequality does not mean being content watching children starve and nations crumble. Rather, it means accepting differences in human ability (and hence what sorts of value people can produce), and then looking for win-win solutions that include a better life for all people that choose to be part of society (e.g. by following The Silver Rule).
A more fitting analogy than "life is like LoL" (or some other zero-sum game) is life is playing sports. If you play sports with people around your skill level, you'll have fun, get exercise, and make friends. Sure, individual games are zero-sum games. But the experience of playing sports generally is not. That's why people keep doing it and will always do it, as long as humanity is still around.
Is life unfair because typically men can lift heavier objects than women chan? Maybe, maybe not. The same answer to that question also answers the question, "is life unfair because women typically live longer than men". These are differences nobody chose but that we must cope with, whether or not we want to.
As the Old Testament story of Cain and Abel teaches us (I'm assuming reader familiarity with this story)...
Don't murder, lie, cheat, steal, and obfuscate because someone else is doing better. Do your personal best.
Cries of "racism", "sexism", [...], and ableism (discrimination in favor of able-bodied people) echo across university campuses, into the human resource departments of major corporations, and out into society.
Will Cain use the gun of political power to take from Abel (or take his life), eliminating the competition that made him butt-hurt? Or, can he live and let live, play nice, and find a win-win solution (eating meat & vegetables anyone?) with Abel?
[1] See my essay "Answering the Singularity, Ethically: Ability, Artificial Intelligence and Anarchy" for more thoughts on the topic of automation and ethics.
[2] This statement is rhetorical; of course there are people that are the best at "being themselves", the world does have a fastest runner, etc.