I live in the US and I don't see the division you're speaking of. It's more like:
* entitlement and statist culture votes left: yuppies, inner-city citizens, welfare recipients, Marxist idealists, etc.
* self-reliant and culturally conservative culture votes 'right': business owners, contractors, people who depend on strong economic growth for livelihood
IE, it's not a racial thing. (Of course, there's a looooot of back and forth. Eg. a small family farmer voting for a Democrat (eg. left) because of farm subsidies but also voting for a Republican for another seat for moral/ethical issues. There are quite a few single-issue voters in the US.)
Populist states - NA, CA, NJ, etc. - at the top of the redistribution curve, and due to their income have less to lose by increased taxes. The threshold between "what I make" and "just getting by" is significantly larger, not only as a percentage of income but also absolute dollars.
I've noticed there seems to be a fairly significant association between "people who do the actual market production and keep things moving" and conservative voting habits (eg. engineers, business owners, laborers, and other male-dominated fields) and "people who do high-level/service work and 'liberal' voting habits. The more abstracted from the everyman's existential needs, the more likely they are to vote with a leftist policy.
When you're making 30k, a 1% tax increase means you need to make household budget cuts, because that tax increase 'trickles up', to abuse a term used by economists. That 1% tax increase may cost a chunk of your income, but you'll also have to contend with the increased prices of goods and services which results from the increased costs of doing business, which is caused by needing to increase pay of their employees and increased material costs, all caused by people needing more money to cost justify a specific job.
If I'm making $100k a year, I'm probably not even going to notice a 1% tax increase.
Another part of it is ideological affinity. To many people in Western states, it doesn't matter how poor they are. Sure, they want to have more money, but there is a certain pride in eg. the Western US states about being able to say, "I did it my way, pulled myself up by my bootstraps". Ironically, my experience is that it's notably more difficult to actually make a go of a business in these states due to population density, and possibly due to a higher sense of cultural self-reliance and minimalism which naturally leads to less consumption of amenities.
I would be interested in seeing a county wealth heatmap like this, after adjusted for total cost of living (including state and local taxes). I'm in South Dakota, where we have no state (income) tax, sales tax is 4%, and municipal taxes aren't more than another 2%, IIRC. $40k here goes a lot further than $100k does in eg. the SF Bay area or downstate NY. On 40k, you can comfortably (with spending discretion!) start a family, buy a house with a yard in a nice neighborhood, have paid-off used-in-good-condition vehicles, have money for vacations and/or activities, and not live paycheck to paycheck. That's with a single income, I might add.