How is that possible when it seems like every place is hiring? It's obvious that retail/restaurants are short-handed, but every manufacturing company in town is hiring. Every week there are articles in the news talking with business owners about how hard it is to find people, people accept the job and don't start, they quit after two days...
A few years prior to the pandemic, my brother shared a story from the medium-sized manufacturing company he worked at. A rumor started that an "ICE raid" was going to occur sometime during the week. Something like 1/2 to 2/3 of the factory workers didn't show for work over the next couple of days. Even assuming it was less impact than that, it seems to say that a significant number of factory floor workers were in some kind of position that caused them to fear ICE.
I am . . . bearish . . . on trusting news articles about this topic. There are just so many incentives to shape articles to get clicks . . .
You're not going to find out the exact breakdown with a self-selected sample of a few hundred Hacker News readers.
As for an explanation of why churn rates went up so much (that is, people are quitting jobs at a much higher rate even if they largely are not completely leaving the workforce), that seems pretty easily explained by the move to remote work. I'm not meeting your criteria here because I didn't change industries, but as soon as it became possible to work for a Silicon Valley software company paying much higher rates than any local company without being required to relocate, I absolutely did that. Labor has far more options now that they aren't limited to only working for companies with an office within commuting distance.