They're only "widespread" as a result of the last couple years, when their effect on human populations was studied at large and in the wild. They weren't widespread before 2020, when they'd barely entered human trials. "Some of the most widely used and studied vaccines in existence" is gonna need something to back it up, because we've been studying classical vaccines for decades and using them on cumulatively far more people.

It's perfectly reasonable for someone to decide that they don't want to use a novel therapy. What's weird is when other people claim that that decision means they're anti-vaccine.