My experience living in an area that has high net migration from California is that the people leaving bring California's policies with them.
Sure everyone's land is worth more (as if selling the home you own or the land your business is on is actually an option when you can't readily replace either) but at the end of the day but everything winds up inflated and your standard of living flat-lines or decreases despite the increased stress.
One guess I'd have is that an influx of new people creates that anti-housing response anywhere which can lead to some of the same problems. I suspect that's less about CA policy and more about bad incentives around housing being an investment in the US.
If you mean that most people from CA don't like Trump (or the Republican support/defense of him), then yeah I think you're probably right about that (but that's not really CA policy). A lot of people I work with are more center or center-right than the general narrative about Californians would have you believe, I'd suspect those leaving to be more from that camp.
What people don't like is that when upper middle class city and inner suburb types move in local ordinances that restrict what you can and can't do on your own land seem to always follow. And given a generation or so of change in that direction, it gets you the same overpriced, impossible to develop hellscape that those people were seeking to flee in the first place. This isn't unique to CA. Their stupidity isn't special. This pattern has played out all over the east coast and midwest.
1 - anti-housing like you say. You see lots of signs in my neighborhood wishing against more-dense housing, despite (relatively) astronomical pricing. At least in Seattle, we do have an issue where we're constrained by water so there isn't a lot of places to build that aren't very far out. So density really is the only solution if you're going to keep computes reasonable. The only people who can afford to buy the existing not-dense housing have a ton of money or income (or both). A >$1m SFH is just not affordable in a city where median household income is $100k.
2 - push against increasing property tax. Sort of a corollary to the housing bit. Which gets doubly odd because we have no income tax in WA. Weirdly regressive.
3 - the strange and ineffectual CA-style push against "assault rifles" as the main item of gun control, despite the fact that all rifles nation-wide kill ~300/yr while pistols kill 30,000/yr, 10k of which are homicide. I say ineffectual because Amdahl's law is a thing, so even if you did magically disappear all riles in the country, it would have a ~1% impact on gun violence.
4 - restaurants heating the out of doors. This spiked a lot with coronavirus so it's hard to talk about now. (This might also be me projecting because I myself am an implant from the Midwest (yes I am a hypocrite), and heating the out of doors is just complete insanity to me)
5 - Many more good restaurants in general though. Sadly, still not a lot of good mexican restaurants.
6 - a change in coffee styles. Take from that what you will, people are kinda religious about it here.
It's really hard to pick out what's actually influenced by CA implants, vs what is just homegrown.
But it is crazy inefficient to pump heat into the outdoors. It's not as inefficient in most parts of california, even northern california. But when you move north it gets down under 40... (In the Midwest where it gets below 0, it's complete lunacy)
It's a weird thing to be simultaneously in favor of environmental controls and trying to raise awareness for climate change (and doing things in Seattle like banning the use of natural gas for heating?), while also being totally ok with heating the outside for dining.
The real problems I see are more cultural ones. Homelessness is rising (as it is throughout the US). Utah had handled homelessness much better than other places due to a unique balance between the local government, the police, and the LDS church (I'm not a member FYI), but changes in the mayor and chief of police disrupted that balance.
I also perceive an arrogance on the part of some of those moving here. The idea that they can just start changing things without understanding how/why things were the way they were before. I don't think I'm against change--it's impossible to stop it in any case--but I also don't think coastal values are right for every area.
Not exactly a novel proposition. The Europeans who arrived in what is now New England, or the Caribbean or yes, even Utah, felt much the same and acted like it too.