If it was a rejection of anything, it was of any assumption of good faith on the part of either government or scientific institutions. Why that happened, as quickly and thoroughly and as polarized along clear partisan lines as it was, is a mystery.
It isn't a mystery, it was the bullshit and lies that happened the first month of covid in USA, many people then stopped listening even when the bullshit and lies stopped. I remember the cases in New York exploding and the local democrat told people to continue as normal since its nothing to worry about, and that masks doesn't prevent spread so don't go buy masks, that was how it all started.
They say they had to tell those lies to save resources for those who needs it, but that made people stop trusting them and that counts for so much more. I hope they learned their lesson, but likely they didn't as they never said "Sorry we lied to you, we shouldn't have done that".
People literally formed resistance organizations and were warning of a global fascist takeover, we were entering an eternal police state in which the unvaccinated would become a slave underclass and if you didn't have your vaccine card you would get shot dead in the street.
All of it went far beyond simple mistrust in the government's PR.