Part of the problem here is that you take a strictly logical/intellectual approach to what is essentially an experiential teaching. Zen tries to subvert exactly this type of critique with its koans, which attempt to short circuit the rational mind with apparent absurdities and contradictions. I am no enlightened sage, but I have had experiences which have given me some insight into transcendent states. I have, for example, experienced excruciating kidney stone pain and at the same time become aware of an observer in myself who watched my experience with detachment and even joy. Not joy at the suffering, but a kind of joy in the pure freedom of consciousness beyond transitory experience. Language is ill suited to such states, and thus one may misconstrue the words used to describe them, saying for example that this observer must be a nihilistic one because of its indifference to my suffering. But both indifference and nihilism would falsely construe the experience in terms of known categories. Non-attachment is not detachment or indifference. The possibility of compassionate, non-attached awareness may seem contradictory in the absence of any experience of it, but history is rife with the misapplication of concepts beyond their frame of reference, such as the argument that the earth could not revolve around the sun because then everything would fall over - it seemed obviously true to those who argued it, but was based on a misunderstanding of motion as something absolute. Such an argument: “you wouldn’t understand because you haven’t experienced it” can seem supercilious of course, which may be why Zen masters preferred koans.