Jun seems to have lost faith with all of the institutions of his world—the government, the church, school. And his argument that everyone is pretending seems to imply he had lost faith in people as well: he had come to see lies as the primary thing in the world. While one might see Jun as a truthteller fighting against lies, it's also possible to see Jun as a depressive. Regardless, it’s unclear whether Jun himself is telling the truth about anything, though Jay himself seems to not yet have realized this.