Seeing as at first they said any unexpected reaction would be impossible because "science" and then reports of myocarditis came in and people said "impossible" which then became "maybe" which then became "yeah, in some cases, but the disease is worse!"
The tech was new enough we didn't know about the myocarditis potential side effect. Everyone was so sure, just like you seem to be. "It doesn't work like that" -- except it does cause myocarditis in some patients
All the while forgetting that benefit is heavily skewed.
Those that would really benefit from its protection are often the same group that would be knocked sideways by its side effects (the very old, infirm, already sick or otherwise vulnerable).
The majority get nothing much in terms of side-effects, but also nothing much in terms of protection over what our bodies could already do for us.
There’s only a small group that are vulnerable enough to benefit significantly, while also being strong enough to tolerate it.
The tech was new enough we didn't know about the myocarditis potential side effect. Everyone was so sure, just like you seem to be. "It doesn't work like that" -- except it does cause myocarditis in some patients