Jesus' parables both reveal and conceal. Jesus was partly in the role Isaiah had been in: announcing God's grace and judgment, and watching his people choosing a path toward disastrous judgment, destruction. So many were unable to believe him that God was calling them to a new path for a new time. They had their own ideas about God's kingdom and Messiah.
Jesus saw things through a different lens with different purpose. He called everyone, including the "pure," to transformation in the midst of a broken world. Radicalism of "us pure" against "them impure" is popular. Radicalism of transformation by God's gift of grace is hard. I want a Messiah that recognizes how good I am and invites me, rather one that sees how broken and weak I am and transforms me. Jesus doesn't kick out the tax-collectors or the Pharisees.
Be wheat? That's not exciting. I want to be a revolutionary, a change agent. I want to be part of an elite, pure community sent on hard missions for God. Well, maybe? There are