"Do not judge" in Matthew 7:1 does not... cannot... mean to never judge. To rightly judge is a heart posture. When we recognize the great mercy we have received through Christ, two things happen:

1. We recognize how great is our sin of which we have been forgiven and
2. Our hearts soften to the needs and shortcomings of others, freeing us to move toward them in ways that are genuinely helpful, not merely reactive.