Guessing they like some combination of geography, neighborhood, house, job where they live?
There is no political back and forth like there used to be where you'd have republicans controlling things for a time and then democrats. It's been mostly Portland democrats controlling the state for over 20 years now. The needs of most of the state, by geography but which has a lower population, are not the same as those in the 1 big city the state has, so a lot of people are interested in changing that with democratic votes.
Since Portland pays the lionshare of taxes for the state, you'd think they'd be happy getting rid of the poorer parts of the states that they have to currently subsidize. Seems like it would be a win-win for everybody involved. What are the downsides?
If you look at the state senate map, there is a lot more red land mass than blue. https://commons.wikimedia.org/wiki/File:Oregon_Senate_map.pn...
A few are farmers. Looking back a generation or two most of the people in southern Oregon were employed by the timber industry - that number has shrunk considerably over the last generation. There are Eastern Oregon ranches but they tend to be pretty large so not a whole lot of actual farmers/ranchers in total. Yes, they employ people to work on those farms/ranches. And yes, the counties involved in these votes are pretty sparsely populated, but I'd be surprised if even as many as 20% are employed in agriculture at this point. Here's some data from the ODA:
"Oregon’s principal operators of farms and ranchesmake up less than one percent of the total population of Oregon. However, when paid and unpaid on-farm workers are included the total number of workers on the farms and ranchesincreases to approximately four percent of Oregon’s population." [1]
> There is no political back and forth like there used to be where you'd have republicans controlling things for a time and then democrats.
I'm old enough to remember when Oregon Republicans were by and large quite liberal - at least the ones who actually won statewide elections (Tom McCall, Mark Hatfield, Packwood - all Republicans, all would be considered quite liberal today). Both parties tended to have liberal and conservative wings back then, but the conservatives didn't win many elections.
[1] https://www.oregon.gov/ODA/shared/Documents/Publications/Adm...
I have yet to come across a land mass that has a political leaning.