It is common place for people in the church to complain that those of us who are in the business of apologetics and discernment are only succeeding in making enemies within the Body of Christ and not interested in engaging in reconciliatory dialog.
Across all 27 books of the New Testament the writers either directly engage in or tell stories about people who confronted religions of their day (including their own) to challenge their beliefs and to bring them into a saving knowledge of the Gospel.
Look at Christ’s own interactions with the Pharisees and how he would curse and them publicly for forsaking the work of God for their own contrived rules and power. Not only did he call them names, but essentially said that their life’s work was in vain because the entirely missed the message of the Old Testament. Indeed its fulfillment was standing before them and they did not recognize him. There was never a drove of Pharisees that came to a salvation after these encounters, but was it Christ’s intention to change them or to change us?
Some of these were more gentle and some were quite harsh. Take, for example, the opening lines of the book of Galatians where Paul openly curses those who would preach a different, therefore false, gospel. In case you missed it, being cursed is not a very good thing. Led by the Spirit, we can rightly discern the truth from the lie and therefore avoid being accursed ourselves.
As the old hymn says, we are “prone to wonder” from the truth because of our proximity to sin. It is easy for us to lose sight of the truth of the gospel as the early churches did. Discernment is for those who God had called as his sheep, who seek to know more of who God is, and who need the regular herding to stay in the fold. Discernment is about listening in earnest for the voice of the Shepherd, the one we recognize, and the only one who leads us to life.