"Has it never struck you that a man who does next to nothing but hear men's real sins is not likely to be wholly unaware of human evil?
Chesterton, G. K. (Gilbert Keith) (2011-03-30). The Innocence of Father Brown (p. 15). . Kindle Edition.
The question is posed by Chesterton's fictional Father Brown, whose straightforward understanding of the depravity of the human heart and his nearly prescient observational skills allow him to solve crimes.
In some ways, no group of people is more likely to view the actions and motives of people with less naivete than Christian clergy.
Why is that?
First, because the Bible teaches us, as it does to all Christians, that human beings are born in sin. (Explaining why God had to become a human being, albeit one without sins, offer Himself in sacrifice for our sin so that all who turn from the sin and trust in Christ to forgive their sin with His grace gain forgiveness and new life with God.)
Second, we clergy, by doing our daily work in the light of the Bible's testimony about God and humanity, become witnesses to the full range of sin's effects and sin's manifestations in human beings. They come in the form of the person in the mirror who so often disappoints us, in the parishioner or local community member not associated with your church who figures their secret is safe with you, and even in the Christian completely oblivious to his own shocking sin and of his need of the grace of Christ.
That's why I find Chesterton's fictional detective Father Brown so plausible. Though society deems we clergy types as naive--and we may be deliberately so at times--remember that Christians have been told by Jesus to be as wise as serpents and as innocent as doves. Father Brown clearly takes Jesus' words seriously.
By the way, the abrupt and simple ways in which Chesterton's stories end, without fanfare, is fun.