Read the whole Bible instead of repeating feel-good lines from Sunday school. But now I have written unto you not to keep company, if any man that is called a brother be a fornicator, or covetous, or an idolator, or a railer, or a drunkard, or an extortioner: with such an one no not to eat. We aren't supposed to keep company with any believer that's in fornication. They're supposed to be kicked out of the church. For what have I to do to judge them also that are without? do not ye judge them that are within? But them that are without God judgeth. Therefore put away from among yourselves that wicked person.

The attitude of "never judge anyone for their sins" is called being puffed up. You're fluffing yourself thinking your righteous when you're condoning and encouraging sin.