BS. I have objective evidence that you exist right before my eyes. It is self-evident, and it does not have to be "tested" first to be objective.
That anybody would think that subjectivity is the basis of all knowledge claims is illogical.
It is not "illogical." It is a simple statement that may be true or false; reasonable or unreasonable. In this case it is unreasonable, and for that reason I have not made such a statement. I have never believed subjectivity to be the "basis of all knowledge." I have claimed, and continue to maintain, that science cannot entirely divest itself of subjectivity any more than it can entirely divest itself of human observers.