One of the most perplexing features of false teaching is the way that it clings to orthodox words and institutions. Whether knowingly or otherwise the charge has been made that this is dishonest. Not merely intellectually dishonest but morally so.
There is a long, and ugly, history in the church of confessional statements being retained but their meaning being subverted. There is a similarly tragic tale of once orthodox institutions departing from the vision and theology of their founders. Those in error are often left with the power and the property. They have departed from the truth but have at the same time entrenched themselves in the visible institution. This has been the story of churches, seminaries, and denominations.
Daryl Hart, in his fascinating and compelling biography of Gresham Machen, points out that in Christianity & Liberalism Machen:
...attempted to show under traditional theological headings that Christianity was a religion of grace and redemption, and that liberalism, while using traditional Christian phrases, was a religion of morality and human goodness.
D. G. Hart, Defending the Faith, p. 69
This phenomena exacerbates the problem of dealing with heresy. It is a phenomena often bolstered by an attempted philosophic, theological, and even historical justification of their position by those in error. At times it boils down to a battle over exactly who are the rightful heirs of "Evangelicalism," "Anglicanism," or "Presbyterianism." In such situations appeals can be made to the breadth of interpretation in a movement's history, as well as to the extremism of those who insist on particular doctrinal matters. Amazingly attention can be switched from intellectual arguments to the character traits of purists.
Having departed from the faith there is no guarantee that there will be a willing departure from the institution.
Having noted the same problem observed by Machen, Warfield in his article "The Essence of Christianity and the Cross of Christ," (written some nine years before Machen's volume appeared), made this intriguing point:
It may be, as Troeltsch seems to suggest, that "Liberal Christianity" lacks the power to originate a church and can live only as a kind of parasitical growth upon some sturdier stock. It may be that it is not driven by internal necessity to separate itself off from other faiths, on which it rather depends for support.
The Works of Benjamin B. Warfield Vol. III: Christology and Criticism, p. 444
This could be one reason why, having altered their theology, some preachers seek to hold on to their orthodox credentials and the constituency they belong to. Perhaps it is a tell tale sign when their books and conferences make a direct appeal to the disillusioned and disaffected followers of the host movement.