/sci/ - Science & Math

Kind of soft science, but what's the benefit of equality, many people (independent of political, social, financial factors) accept equality of everyone regardless of race/sex/... to be such a fundamental principle that it doesn't even need motivation, and resort to arguing only about how it should be implemented, but why? It's not a universal view in all cultures in history that everyone is equal, unlike values such as 'dont kill random people', which is almost completely universal, and has a clear benefit for the society as a whole.

Arguments I've heard are
>Imagine if people weren't equal and you were one of the oppressed people
Which is literally an appeal to emotion and can be used to justify anything (imagine if you were on death row, thus death penalty is wrong, for example)
>The recent increase in inequality has also caused an increase in unhappiness
No sources or further motivation are ever given on this

In memes: what's the evolutionary purposes of equality?