i don't think its about a lack of exposure to the concept of subjectivity and objectivity as much as it is a fundamental disbelief in anything approaching metaphysics whatsoever, which yes, stems from the absolute belief in a purely physicalist understanding of the universe. the difference between physicalists and myself is similar to the difference between an atheist and an agnostic. the atheist assumes that there is and can be no god or gods, whereas the agnostic makes no assumptions whatsoever regarding this. the physicalist assumes the ability of their belief system to be refined into perfection without much in the way of fundamental revision, assumes the nonexistence of any phenomena that cannot be described by physics, whereas i believe that one or several paradigm shifts in philosophy and science and the philosophy of science are necessary to improve our understanding of reality, i do not assume that the physicalist model of the universe is correct or able to be trivially modified to be correct. and when analysis in fact shows the inability of physicalism to explain a phenomena we all experience every waking moment of our lives like subjectivity or qualia, i take that as evidence against the model, instead of ignoring it in the hope that someday the model might be trivially revised somehow to account for this fundamental explanatory gap.

a 'unified theory of everything' may or may not be possible, but it should be especially possible under physicalism - if everything is indeed reducible to physical matter and physcial processes, then surely we should eventually be able to describe matter and related physical processes in sufficient detail to describe all of reality, including subjectivity. but i don't think its necessarily physicalist to believe humans can comprehensively understand existence, for example if subjectivity is fundamental to reality in a way similar to matter, then understanding subjectivity and matter both, and their relationship to one another or to whatever reality they both refer to, could help us understand existence in a more coherent sense.

thats' the entire point. if the existence of complex unconscious behaviors (or even just computers and math) proves that information processing can be done without internal subjective experience (if we assume a stone being hit by another stone, for example, is not experienceing subjectivity), and if there is something humans do beyond what is possible for pure information processing, then that is proof that consciousness is fundamentally irreducible to it. if there is something we can do that a philosophical zombie (a person with information processing but not subjectivity) could not, it is because of subjectivity/qualia, not information processing. subjectivity can influence our information processing but is not identical with it.