Do you suppose, O man—you who judge those who practice such things and yet do them yourself—that you will escape the judgment of God? Or do you presume on the riches of his kindness and forbearance and patience, not knowing that God's kindness is meant to lead you to repentance? Romans 2:3-4 (ESV)
It's part of the human condition for us to slip into patterns of judgment. We feel more comfortable when we can place people in "boxes;" as though the messiness of human relationship is more manageable when we have measured and quantified others.