There will ALWAYS be false Christians who are within our faith and using Christianity to lead us from the truth. How you go about it is wrong. We all are bound to confront unexpected challenges that will strike us with the fear of the unknown. We have to remember that faith is effective when there is unity.
Judging based on appearance and doctrines are man-centered more than God-center. Appearance is one thing but fruit of the Spirit is the other. "You should not judge", is not the same as "fruit inspector", or "discerning true and false teachings". People who don't discern are those who are "ignorance". Its really interesting about people are mixing "judging" and "discerning". Jesus gave us the formula for finding out "false prophets," but the devil are using people to tell us we should "not judge." So people are telling us: "God didn't make you a judge so therefore do not inspect fruits." Jesus gave us wonderful examples and one of His great example is "By THEIR FRUITS you shall know them" Christians are too look at the WHOLE package of a Christian. Do not have a tunnel vision" based on their teachings alone. You need to look at their whole being. By THEIR fruits, you shall know them. The problems when we look at their fruits, we judge based on doctrine rather than spiritual salvation.
I believe that each of us, as an individual, have a responsibility before God, to determine what is true about God and also what is false. What is true about God impacts every aspect of our lives.
For AN EXAMPLE, I could even consider you a false believer because of how you believe and how you control the forum. ( I am not saying you are, but you are doing this). Using knowledge without facts can easily lead us to a clearly false conclusion. Conclusions drawn in this manner are usually overgeneralizations.
"I am the true vine, and my Father is the gardener. He cuts off every branch that doesn't produce fruit, and he prunes the branches that do bear fruit so they will produce even more." Jesus Christ John 15:1-2
Are we allowing God's will in pruning us so we will bear more fruit?
Are we judging Christians and non-Cristians? For as we judge others so we will be judged by God. Are we heavenly minded or earthy minded? In Romans 14:5 "One man considers one day more sacred than another; another man considers every day alike. Each one should be fully convinced in his own mind." 1 Corinthians 10:28-29 "both for the sake of the man who told you and for conscience' sake, the other man's conscience, I mean, not yours. For why should my freedom be judged by another's conscience?" Romans 14:10 "You, then, why do you judge your brother? Or why do you look down on your brother? For we will all stand before God's judgment seat."