I would require of them a clearer explanation of what they mean. I don't see in verse 16 what you (they) express above. It makes no sense.
In a more general sense though - NT Scripture describes a church (ekklesia) that is highly unified and structurally authoritative. In addition to 1 Tim 3:15 there are many other verses that point to the Church being God's authoritative body on earth.
I usually begin with what I see as the most clear example of a) instruction and b) implementation of authoritative Church in the NT.
Mt 18:15-18 has Jesus telling the faithful to "Tell it to the Church" when there controversy. The Protestant might respond that this refers to "Sin" in verse 15 - to which you can ask them if teaching a false gospel is or is not a sin. The obvious answer is that it is indeed a sin to preach a false gospel - so Mt 18:15 would apply to doctrinal matters as well as personal sin.
The protestant will then often say that the "church" referred to in Mt 18 is the "local visible body" and not some universal body. But this is shot down in Acts 15
Acts 15 is the example of the universal Church acting Authoritatively. Members of one local body/group created friction with another local body/group. Not even the great Apostle Paul could bring about a resolution. So the matter was taken before the Apostles and elders in council - in short they "Told it to the Church", and the Church ruled on the matter, not just for the couple of local bodies involved but for ALL of the local bodies that made up the one ekklesia - Church.
Couple these very powerful passages with the many admonitions and encouragements from Christ and others:
20 "I do not pray for these only, but also for those who believe in me through their word, 21 that they may all be one; even as thou, Father, art in me, and I in thee, that they also may be in us, so that the world may believe that thou hast sent me.
5 May the God of endurance and encouragement grant you to live in such harmony with one another, in accord with Christ Jesus, 6 that together you may with one voice glorify the God and Father of our Lord Jesus Christ.
1 Cor 1:10
I appeal to you, brethren, by the name of our Lord Jesus Christ, that all of you agree and that there be no dissensions among you, but that you be united in the same mind and the same judgment.
2 Cor 13:11
Finally, brothers, rejoice. Aim for restoration, comfort one another, agree with one another, live in peace; and the God of love and peace will be with you.
Only let your manner of life be worthy of the gospel of Christ, so that whether I come and see you or am absent, I may hear of you that you are standing firm in one spirit, with one mind striving side by side for the faith of the gospel,
1 Pet 3:8
Finally, all of you, have unity of mind, sympathy, brotherly love, a tender heart, and a humble mind.
After presenting all of these things that point to a unified, universal, authoritative Church built on a councilior model - something that is clearly seen in BOTH of the ancient Christian Churches (RC and EO), ask your "bible believing" friend to show you from Scripture equally strong evidence for the Protestant model of local independence, invisible body, private interpretation of Scripture etc....
I have yet to find a protestant who can do so. At most they try to say that I am not interpreting correctly...and given a very few verses that are easily shown to be in perfect agreement with the universal authoritative view....but mostly I am met with silence for the Bible simply does not support the protestant model of Church structure.
As regards the reference to controversy...We can (and do) still have plenty of that within the Church.