Inequality & Unhappiness

Human beings generally tend to accept the rich if they earned it in a just way. Problem starts when injustice sets in. If rich people earn a lot of money relatively conveniently and/or unjustly, then poors want to end that system of injustice.

Recent studies show this behaviour in other primates too. Does Inequality Make Us Unhappy? - is a thought provoking read.

On a side note, I remember one type of theistic argument on morality is that, the system of justice is independent of human society which has a divine origin. I think this article with the help of scientific studies on monkey behaviour, proves that our sense of justice has evolved from lower animals. In other words, lower animals also have this sense of moral justice and equality.

I always wonder, why can't the theists realise that the holy books written by these ancient goat herders always reflect the morality of their own societies?