What's the problem with inequality after accounting for other societal ills, faulty causal inference, and human psychology, such as:
Poverty
Lack of social mobility
Lack of opportunity
Widespread mismatch between worker skills and employer needs
Status competition
Perceived unfairness
Social comparison blues
Envy
Resentment
Mistrust of the System, eg capitalism
Mistrust of others
Us/them mentality
Suspicion of undeservingness, eg, illegitimate gains by the wealthy
Zero-sum understanding of wealth
Lack of hope/optimism
Misgovernance, e.g, regulations that benefit a few favored groups but undermine economic growth and vitality
Weak economic growth
Corruption
I suspect some will object that other societal ills are exacerbated by inequality or that the above perceptions and emotions are onto something that really exists. To which I say: show me (with rock-solid evidence).
Causal attributions matter, because policy matters. Attacking the wrong problem makes for bad policy.