This is true, there are no absolute rights. However, the examples you cite have no resemblance to the stifling of careful discussion which might, in some way, question the wisdom of universal vaccination or inquire about the long-term effects, etc. That kind of speech is qualitatively different from incitement to violence and other clear and present danger cases. So I'm not sure how pointing out that in some abstract sense rights are never absolute has any bearing on this discussion. The chilling of speech in the public square that we are currently witnessing has no clear limits and the logic used to justify it ends up making this tantamount to setting up some kind of a wrongspeak standard. In a free society, individuals must be uninhibited in their investigation of the wisdom of public health policy. Equating this to the "yeling fire in a crowded theater" case is silly.