It can't be really annoying to only me when people take this whole postmodern thinking about truth to this level.

Just to cut through all the bullshit: You exist in some sense. Truth or no? So truth does have to exist in some capacity in all things, and its ridiculous to say otherwise. Even if you do have to frame the context to account for silly brain in a vat theories, nuggets of truth can, do, and abundantly exist.