thankfully it's not too hard to avoid, at least in the US—all one needs to do is find someplace to live where it gets cold in the winters, while avoiding highly-concentrated population centers.

Lest we not forget, there is Detroit

like I said, while avoiding highly-concentrated population centers... the population density of Detroit is over 500x of that where I live.

our country is huge—why restrict oneself to living in extremely dense population concentrations?

There is no shortage of small towns in cold places that have been devastated by meth and fentanyl where crime is hopelessly rampant.

In review, your two glib panaceas of moving somewhere cold or moving somewhere less dense are hopelessly inadequate.

after living in the greater Seattle area for a few years, visiting San Francisco in 2016, visiting my wife's family in northern Idaho, and living in South Dakota for most of my life, I would much rather live in either of the two latter places than either of the two former places, when it comes to crime. and general societal cohesion. and lack of poop on the ground. by a longshot. not even close.

Those "progressive ideals" have long since ceased to be progressive, ever since the "progressives" gained more or less permanent power in those places. Progressives should not remain in power for too long since they are not capable of recognising a local optimum and keeping those policies which have been shown to work. Conservatives should not remain in power for too long since they are not capable of recognising the need for change when external or internal factors have made the traditional way of doing things obsolete or counterproductive. What is needed is a balance between the two, a form of checks an balances on ideology.