Good ole Matthew 7. This is one of those passages always taken out of context. We have the writings of Paul which says to make sure that we are not allowing false teachings in the church. We are supposed to judge other Christians by the word of God.
1 Cor. 5:12 For what do I have to do with judging those outside? Are you not to judge those inside? 13 But God will judge those outside. Remove the evil person from among you.
In Chapter 5 Paul tackles the issue of sexual immorality in the church. He says to deal with it by telling them to change their ways or be put out. He says in the same chapter that a little bit of leaven leavens the whole loaf. he says to toss out the old bad leavening.
This concept that we are not to hold our brethren accountable for false doctrines is totally against scripture.
If you call yourself a Christian then you must be held accountable to the teachings of scripture.