Yes, and even after 30 years you might still say, "but what about 50? What about 70? How do we know it won't contaminate our bodies after death and leach dangerous toxins into the soil hundreds of years from now when our coffins break down?"

At some point you have to decide to balance the risk in some way and make a choice. Or live your life in a perpetual state of epistemic uncertainty & indecision. In most cases people are fine doing this: very few people refuse to drive over the unlikely possibility of a fatal car accident, or live in a basement on the remote possibility that a tree or meteor will fall on their home.

Unfortunately in this case, politics entered the equation. People cling to epistemic uncertainty to justify consistency with their political allegiance rather than make a decision on the basis of balanced risk, because they they have chosen a balance point that would make them an agoraphobic recluse if applied consistently across their life.

I withhold that judgement for those who are reluctant due to the "emergency" approval (in the US) but plan to get vaccinated when fully approved (which Pfizer now has received). I might disagree, but I think a rational person could still balance their risk on that "emergency approval" point. So long as they also are consistent in their application of risk balancing to recognize that strong precautions to avoid infection were required in the meantime.

As I said in comment above, we know that drinking water cannot be bad for us, because all organism drank water all through their evolution, and if it was bad in some way, natural selection would have selected those that incurred damages caused by water drinking...

But it didn't happen even after so many years, so we know that drinking water did not make us less capable.