Science is hard :p

Good poker players can lose all their chips at the table to an unlucky draw and walk away knowing that they made the right play and that they'd do it again, even if they got unlucky on the river card. Good basketball coaches will still draw up plays to get the ball into the hands of their best shooter at the end of the game even if they miss sometimes.

If you're choosing between option A that has a 0.0001% chance of hurting you and option B that has a 10% chance of hurting you, and you choose A and still get hurt, that doesn't mean you made the wrong choice or that if you have it to do over again you should choose B.

In reality, we don't have that. We get whatever ideas have the largest marketing budget behind them, and we just have to trust them. It's more like "nobody gets fired for buying IBM (or pick your favorite pundit)" than running a poker scenario through a solver. And that's fine, I don't think you can expect much more than that out of people.

The stupidity of requiring people that already have antibodies to vaccinate, or even to require people to vaccinate. If you are worried, vaccinate and that's it, you are protected, don't impose others to do it. Especially a novel experimental vaccine that changes your genetic code.