Couple of Points:
1. My family made regular trips to Seattle for various reasons from 1979 onwards, and for ~80% of the time from 1992-2014 I lived within the city limits: U-District, Ballard, Phinney Ridge, and Capitol Hill. I live about 12 miles north of the city now, and find myself either passing through or in the city a few times a month.
Does saying that you liked Seattle much more when the public spaces in Seattle were safer, cleaner, and more orderly and resenting the people and policies that have made it much less so mean you "hate" Seattle? If I expressed hostility to someone dumping industrial waste and raw sewage into a river that I lived alongside, the policies that made such destruction possible, and the people supporting what I deemed to be profoundly irresponsible, reckless, delusional, and misguided policies that enabled such pollution - could that only be motivated by a "hatred" for the river? Perhaps it might be the opposite?
I've seen and lived with the consequences of various policy regimes instituted by the city with my own eyes over the course of the past ~40+ years, after spending most of my adult life actually living in the city I think I've got every right to express hostility and contempt for politicians and policies that have made the city a worse place to live in - *especially* for people that are poor, physically vulnerable, and need to use public spaces.
I'd be willing to wager that I have connections to the city that are at least as long, deep, and significant as yours, and have considerably more regular contact with people that actually live in Seattle than you do. The idea that you have to be some kind of extreme right-wing ideologue to dislike the direction things have gone in the city, or to conclude that you'd have a dramatically better quality of life elsewhere and decide to vote with your feet and move - be it a few miles outside the city, or over the Cascades - is the sort of conjecture that you can *only* engage in if you live far enough from the city to base your opinions on ideology and very little else.
2. California has a population of 40 million. Oregon has a population of 4 million. Washington has a population of 7.5 million. That's 51.5 million. Idaho has a population of 1.9 million, 800,000 of whom live in the Boise metro. Ergo the population of California + Oregon + Washington = roughly 64X greater than the greater Boise Area. Even if a tiny percentage of the 52 million inhabitants of WA, CA, OR decide that move to Boise and other small cities in the interior of the West, that's more than enough to overwhelm the local housing market in those cities, which is at least part of the reason that 3 of the 15 fastest cities/towns in the US in 2022 were suburbs of Boise.
They're clearly coming from somewhere - and while the net migration figures from a single city that constitutes a relatively small fraction of the total population in coastal metro areas are interesting - without disaggregating them into more granular demographic cohorts the numbers can't tell you much about the impact they'll have on the effective demand for housing or home prices. If you've got that data, I'd be interested in looking at it, but I'd be willing to bet that the cohort moving from Boise to Seattle proper skews heavily towards the young and childless, with a smattering of established adults with the wealth and earning power necessary to buy a home in the Puget Sound these days.
In any event - the idea that outmigration from coastal cities with an exceptionally high cost of living and a deteriorating quality of life isn't driving demand for homes in Boise and other cities like it upwards and isn't having an effect on prices is very difficult to reconcile with the facts on the ground, but I can assure you that it will be very welcome news indeed to anyone who wants to buy a home there.
3. In a very important sense, I'm on *your* team! I personally hope there's a sustained, generational mass-exodus from smaller cities and towns in the Western interior that are nestled amongst rivers and mountains, and that everyone leaving has the means and the desire to pay a wildly irrational premium for a very average home ~10 miles north of Seattle, and that this trend culminates in a speculative frenzy that dwarfs anything in recorded history right when my youngest graduates from high school.