There’s a common misconception that our Lord commanded us to turn a blind eye to evil.

Yes, we are absolutely forbidden to judge others. Jesus was very clear on this:

Do not judge others, so that God will not judge you, for God will judge you in the same way you judge others, and He will apply to you the same rules you apply to others. Why, then, do you look at the speck in your brother's eye and pay no attention to the log in your own eye? How dare you say to your brother, 'Please, let me take that speck out of your eye,' when you have a log in your own eye? You hypocrite! First take the log out of your own eye, and then you will be able to see clearly to take the speck out of your brother's eye. (Mt 7:1-5)

The same admonition is repeated through the Gospels. (i.e., Mt 7:5, Mt 7:1-2, Lk 6:31-37, John 7:24, John 8:7, James 4:11-12, Rom 2:1-3, Rom 14:1-13, Eph 4:29) However, this doesn’t mean we should turn a blind eye to bad behavior. Though it's strictly verboten to judge others, bad behavior is perfectly fair game. The problem is that most people, Christians included, don't know how to make the distinction. It's wrong to say, “You're a bad person!” but it's absolutely required of us to say, if necessary, “What you're doing is bad!” as the Bible teaches:

  1. Faithful are the wounds of a friend, but deceitful are the kisses of an enemy. (Rom 15:14)
  2. And concerning you, my brethren, I myself also am convinced that you yourselves are full of goodness, filled with all knowledge and able also to admonish one another. (Col 3:16)
  3. Let the word of Christ richly dwell within you, with all wisdom teaching and admonishing one another with psalms and hymns and spiritual songs, singing with thankfulness in your hearts to God. (Ps 141:5)
  4. Let the righteous smite me in kindness and reprove me; It is oil upon the head; Do not let my head refuse it, For still my prayer is against their wicked deeds. (Lk 17:3)
  5. Be on your guard! If your brother sins, rebuke him; and if he repents, forgive him. (1Thes 5:14)
  6. We urge you, brethren, admonish the unruly, encourage the fainthearted, help the weak, be patient with everyone. (2Tim 3:16)
  7. All Scripture is inspired by God and profitable for teaching, for reproof, for correction, for training in righteousness. (Col 4:17)

This doesn’t mean we have carte blanche to start belittling and shaming people. Though we have the right to judge bad behavior, Christ demands that we do so lovingly keeping in mind the target of our criticism is a child of God and is indeed well-loved by the same Creator Who made you and me.