In an excellent Singapore econ-travelogue, Scott Sumner writes:
My theory is that leftists don’t really mind a place where income is unequal, they don’t like places where income looks unequal. 
This is close to what pioneering blogger Mickey Kaus has been pushing for since, oh, the invention of the New Democrats.  I’ve never read his 1992 book The End of Equality, but after 13 years of reading Kausfiles I think I’ve got the main idea: Higher income inequality is inevitable, let’s get used to it and let’s respond by increasing civic equality, social equality.  His idea is to tinker with the state so that people feel equal in civic life even if money inequality is high.  In his view, that feeling is a genuine good; I’d emphasize that the sensation of civic equality may prevent voters from killing the goose that lays the golden eggs.  
A few of Kaus’s ideas: Boost the relative status of the work ethic; create universal health care; be skeptical of Wagner Act unionism since it’s insider-friendly and since it leads to awful cars.  A veneer and sometimes a substance of equality in public, decadence for the rich in the privacy of their Village brownstones.  
Here’s a sentence Kaus likes from Reagan’s 1992 GOP convention address:
Whether we come from poverty or wealth … we are all equal in the eyes of God. But as Americans that is not enough–we must be equal in the eyes of each other.
And on Singapore’s Mass Rapid Transit system, we all appear equal.