Sorry, I don't agree with you. Rather wealthy
liberal people in liberal cities tend to force up prices because of scarcity (those places tend to be islands of wealth surrounded by an ocean of poverty and crime). Also wealthy
liberal people tend to prefer downtown or euro-style dense areas (scarce, because the inner-city in America is
generally not a good area). There is no correlation between wealth and political affiliation, rather between age, race, industry/field, etc.....and political affiliation. Let's talk about the latter point. If you work in some industries like entertainement, IT or in some fields like higher education or civil service, you're more likely to be liberal than,......if you're a businessman, an engineer , an army officer or work for let's say, the oil, the agro or the automotive industry.
But generally speaking, outside SF bay Area, LA and Manhattan,...think average american cities like Atlanta, Philadelphia or Houston,....you can assume the red dots are an indication of nice neighborhoods/suburbs with good schools and safe streets.,...and the blue dots,..well, quite the opposite.
Now it also depends on what he means by "liberal",....if he only means cities that vote for liberal politicians and support liberal policies, well, generally they are not the best places to live, and taxes are very high there. If he can't take the heat and only seek well-segregated white ghettos full of starbucks, sushi restaurants, organic food stores and art galleries, in this case he must make at least a 6 figure salary to afford one of those places.
@SusieQQQ
The best places that combine liberalism, safety and relative affordability (relatively, compared to SF and the nice neighborhoods of NYC and LA), are probably in Oregon, Vermont, Western Washington, Massachusetts and Maine. Otherwise, I would recommend him to live in a conservative suburb, and commute to the city (probably very blue) for his dose of liberalism (he has tons of alternatives, Atlanta, Dallas/Austin/Houston, Charlotte/Raleigh, Salt Lake City, Pittsburgh, Indianapolis, Tampa/St Pettersburgh area, Denver/colorado springs, etc...