Societies that are highly unequal might suffer from only a subset of the above. But I would speculate that they probably suffer from most of the perspectives above, maybe even all. Or even from many added others (gender, race, ...)

The main argument that I want to present is that unequal societies are more difficult to understand and require more difficult and complex solutions.

Case one: What is a teacher?

Think about a teacher in your country. Does (s)he make enough to live? Takes a fair sum for work?

A teacher in Portugal, in the top bracket makes around 3100€/month (14 months). My partner, herself a teacher, makes around 500€/month. How? Cannot get a complete time-table and is payed in one of the lowest brackets. Also, every year she has to apply to a new position and it is possible not to get one. In fact she never got one in September, normally staying 1 or 2 months unemployed (again, could be worse - not getting one at all for a full year).

In order to continue my reasoning I would say that, outside of Lisbon, it is possible to have a decent life with 1000€/month (I have lived with that in Porto, know from personal experience).

So, what to think of a teacher's salary? Is it low, it is high? I would argue that inequality makes the answer hard. It also makes policy hard (with the added problem - in this particular case - that unions represent more the top brackets than the lower ones): If you cut 10% of a salary of 3100, that might be acceptable, but might condemn to misery someone living on 500€. So, a reasonable salary cut would have to be more carefully thought than in cases where the variation is more contained.

When such inequality is present, we simply cannot talk of "teachers", as we risk talking of completely different realities. As an information token, the word "teacher" lost value.

Now, if even talking about "teachers" in the media over-simplified and over-manipulated reality is difficult now imagine trying to discuss all this heterogeneity.

Case two: pensioners

Here I am just going to present my grand-father and my father (both getting a state pension): My grand-father makes ~200€/month. My father ~1500€ plus he still works free-lance for his old employer (Allianz) making probably not much less every month with free-lancing (though variable).

Conclusion

In a more unequal society, a rational analyser and decider will have to undergo a more complex cognitive process to deal with the heterogeneity caused be inequality: Looking at medians and means is not enough, full distributions will have to be more closely understood and monitored. Quantitative differences will have stark qualitative outcomes and spill-over effects (externalities) to other areas.

For me, with my background, listening the word "teacher" informs me very little: Do you have enough to eat a proper set of meals every day? Probably yes, but it is not assured. A nice place to live? I really do not know. Are you upper-middle class? It can happen, I know quite a few cases. For me a "teacher" can be all of this. It makes my cognitive perception more complex.

PS - There would actually be a way to start tackling this: high progressivity in taxation. But no "serious" person would propose such a thing...