> there are reports now that teenage boys might suffer myocarditis from the Pfizer vaccine. Incredibly rare, but the risk is not zero.

Another interesting factor at play here is that some people prefer for negative outcomes to come from inaction than action. It's like the trolley problem (https://en.wikipedia.org/wiki/Trolley_problem) when people try to evaluate morality.

In this case, they would rather not take an action (get vaccinated) if there's a chance of harm and would prefer inaction (don't get vaccinated) despite the higher statistical risk of bad outcomes.