Early on in the Covid pandemic response claims of herd immunity were being thrown around and Fauci was claiming a threshold of 60-65% vaccine rate for it to work. As time went on that number kept going up, eventually he admitted that they used a low number to start with only because they didn't think people would comply if the required vaccine rate seemed unrealistically high.

Herd immunity is almost certainly a thing at a certain immunity rate, the question that goes unanswered is what that rate actually is. For there to even be a case for vaccine mandates, of even just the arguments that people ought to get vaccinated due to herd immunity, we have to know the % of immunized population and the risk of vaccine side effects.

My understanding is that we don't have a solid understanding of the exact tipping point for herd immunity, and that at least during the covid pandemic response we didn't have a solid understanding of the true risks of adverse side effects to the vaccines either.

We don't keep up any relevant research to prove that out. Vaccine studies don't use placebo controls, meaning we only know how they compare against what is usually the last approved vaccine. If you tell people that we know for certain that more people would die today without a particular vaccine you're lying, we simply can't know that without testing it.

> And herd immunity protects those that can't be protected by vaccines, your "experiment" would put them at risk as well.

How can we know herd immunity works as we predict it should without testing it? Its an untested hypothesis, and that's totally fine if we're not willing to risk testing it. We can't act as though it is scientific fact at that point though, its a hypothesis that a large majority agree with but that has yet to be tested in any significant way.