Many say we have no right to make a judgment of another person, we all make mistakes, and I agree in great part on that, but when God says something is right or wrong, that is not us judging & we better pay good attention. God’s Word is our final authority. We are not judging (condemning) people when we discern behavior or beliefs that are clearly unbiblical.
Unfortunately many Christians go to both extremes and some think they should not judge at all, they think Christianity means getting along with everybody. This fear of using proper judgment may come from a simple lack of understanding of God’s will, so they start embracing ecumenism & mixing with wrong doctrines, getting little by little out of tract to finally fall into apostasy. Some others go to the other extreme and judge the wrong way, looking to condemn instead of looking to restore, or look to destroy others for their own gain. But we shouldn’t judge according to our own perceptions, rather we should always judge according to the Word of God.
Judge not according to the appearance, but judge righteous judgment. John 7:24 (see Greek interlinear)