1. The Need for Negative Preaching
Members recently left at least in part because the preacher “focused on the denominations too much.”
This is a common refrain against those who stand for truth and against error and take their responsibility to warn against the danger of false teaching seriously.
Is this a valid criticism?

2. It can be a valid criticism
Isaiah 40:1 “Comfort, yes, comfort My people!” Says your God. Ecclesiastes 3:1, 3 1 To everything there is a season, A time for every purpose under heaven: 3 A time to kill, And a time to heal; A time to break down, And a time to build up;
Cf. Matthew 15:1-9, Isaiah 29
If we were to only continually focus on one aspect of the gospel to the exclusion of all else, they might have a point.
Acts 20:27, We must declare the whole counsel of God, which we will see most definitely includes exposing and denouncing error in no uncertain terms.

3. Shouldn’t a Preacher Avoid Foolish and Ignorant Disputes?
2 Timothy 2:23-24 But avoid foolish and ignorant disputes, knowing that they generate strife. 24 And a servant of the Lord must not quarrel but be gentle to all, able to teach, patient, Amen! 1 Peter 3:15, Ephesians 4:15
We must not be arrogant and mean-spirited.

4. Some Disputes Are Not Foolish and Ignorant.
Look at the context of 2 Tim. 2:23-24
2:14-18, Profane and idle babblings spread like cancer and overthrow the faith of some. Names are named.
2:25-26, Correct those in error so they can escape the Devil’s snare.

5. Some Disputes Are Not Foolish and Ignorant.
Look at the context of 2 Tim. 2:23-24
3:1-8, Warning against evil men who resist the truth causing perilous times to come.
4:1-5, Convince, rebuke and exhort those who have itching ears and turn away from the truth.

6. Balanced preaching based on the needs of the hearers
Matthew 11:28-30
Matthew 11:20-24
Luke 19:10
Revelation 2:20-23

7. Don’t talk about others?
Acts 17:16-17, 22-32
Acts 2:22-24, 36; 5:27-32
Galatians 1:6-9, 2:3-5, 3:1-6, 5:4
Matthew 23:1-8, 13-39
Paul called names: Philippians 3:2 dogs, evil workers, mutilation
Galatians 5:12 “cut themselves off”

8. What does God say about false teachers and their error?
False teachers and error exist.
Mat. 7:13-15, 2 Pt 2:1-2, 3:15-17, 1 Jn 3:24-4:1
Error must be refuted.
Jude 3, 2 Cor. 10:3-5, Tit. 1:9-11, 2:15
Those who teach it should be marked.
Gal. 1:6-9, Rom. 16:17-18, 2 John 9-11

9. The erring must be warned.
Ezekiel 3:17-21
James 5:19-20
2 Timothy 4:1-5
The loving thing to do is to warn a sinner and save their souls rather than let them wallow in it and go to hell.