What evidence do you have that inequality is a source of disutility?

Note that if you pull out one of the ever popular left wing scatterplots putting cross-country inequality on the x-axis, I'm going to pull out one with a higher r^2 putting something politically incorrect like single mothers or black people on the x-axis.

As for proportional repersentation, if it indeed is instrumentally useful in creating utility that's fine. But I only care about it insofar as it actually gets us other good outcomes - it's not something I intrinsically value.