Most people see themselves as healthy and thus in the pool of "very unlikely to have complications from COVID-19" pool. Argue with that however you want (people being dishonest with their own perception of health), but that's how they see it. So taking preventative measures because it is forced down their throats seems hostile. Made worse that 1) vax won't stop the spread, or we would have seen that by now, and 2) we need to boost the vax every few months? That sounds highly suspect to a lot of people.

If you were at risk, you can get vaccinated, why force a healthy person? (The answer is mostly for the folks who can't vaccinate, but those folks are screwed any way you look at this pandemic if we are honest).