You brought up a log of topics, some more fringe than others. I think there's been a lot of changes in the world the past few decades that have left a lot of people feeling culturally adrift. Lack of trust in various institutions. Perhaps it is a loss of personal identity, replaced by mass media tribalism? Perhaps the internet is a big part of that - a printing press in everyone's pocket? Finance and globilzation doesn't help. Politicians are not helping.
On the topic of covid specifically, I think that people have vastly different outlooks on the personal and/or societal risks of dying versus the impact of extended lockdowns. I don't think it is an unreasonable position. It's hard to point at definitive data proving that anything works for certain, there's a lot of confounding factors and surprises in the numbers. Some people can't get past the individual tragedies. Some people only look at the population scale numbers. Some people are more educated than other. Lots of people make up their minds on a hunch, as you said, and look for sources that confirm their biases.
A fascinating book I read called "The Republican Brain" talked about this stuff, theorizing that some of the partisan divide is due to personality differences, that people are born with different feelings about authority, hierarchies, individualism, communitarianism, etc. I was left with the impression that this was an evolutionary advantage as a species, that the variety of ways of thinking makes us better as a group.
I don't think that it's the end of the world that we as a group don't agree on everything. We could celebrate that and support each other in our differences, or at least respect each other. But so many do not, both on the left and on the right. They'd rather win 51% of the vote, and impose their point of view on the losers, winner take all. Mass media and further removing isolating people make the problems worse.
> And we still have a non-trivial segment of the population who can’t get vaccinated (under 12) who are quite literally the victims of people who are largely unvaccinated
You called out some things the other side say that are unreasonable. I think the language you used above is a bit strong, and I'm not sure how much fact vs feeling it is. Not a lot of kids die of covid. It's similar for them to the risk from the flu in other years. And RSV. And the vaccine is not 100% effective, lots of people will still die, just like people die of the common cold every year. It seems unreasonable to draw a "quite literally" connection between the vaccinated and the small amount of kids who die, some every year, from respiratory ailments.
Also there is no country in the world who has a 100% vaccination rate, so maybe it is outside the bounds of human nature to expect that amount of compliance on such a short notice controversial issue? Perhaps it would be better for politics to account for the strong beliefs that large segments of their populations hold? For instance, why haven't we build more hospitals in the last 18 months? Are there better ways to support the vulnerable? What are the numbers used to justify various decisions? Can we admit what we don't know? etc