God: "I looked for someone to take a stand for me, and stand in the gap" (Ezekiel 22:30)
To seek unity with false prophets without challenging their errors leaves one’s own beliefs open to questions. Those who defend heretics, even if they do not believe in their teachings, are guilty of lending credibility to their heresies, and will be held accountable to God for the souls that are destroyed as a result. It's up to those that know the truth to defend the Church against false teachers whatever the cost to unity or to personal benefit.
We have suffered from the preaching of cheap grace. Grace is free, but it is not cheap. People will take anything that is free, but they are not interested in discipleship. They will take Christ as Savior but not as Lord.