Romans 14:10Have you ever read G.K. Chesterton's Father Brown mysteries? Poor Father Brown seems so gullible, so easy to deceive, that the criminals always take advantage of him. Unfortunately for them, his appearance is deceptive for he truly is as wise as a serpent, despite his innocence. By the end of each tale the criminal has found himself outwitted by a country parson. Yet the priest's goal isn't simply to see justice done but also to offer the wrongdoer an opportunity to repent, restoring (/beginning) a right relationship with God.
We don't avoid judging our Christian family members because we'd rather live in ignorance, or because we uphold a ridiculous ideal of becoming doormats. Evil runs rampant through this world, including through ourselves, Christians though we may be. Yet love should be at the center of our interactions. We should never treat others with contempt, even when we're challenging them to behave differently. We especially shouldn't judge them and respond with contempt when the matter doesn't concern their morals. Judging a person's actions when they are stealing and calling them to the carpet to repent for their wrongdoing: yes, but lovingly, not contemptuously. Judging their hairstyle as if it were a matter of salvation: no.