In my observation, an apostate is often more moralistic than someone without any Christian background at all. There are a couple of reasons for this:
1.Leaving the faith leaves a void. The void is often filled by substituting politics for theology.
To take a few examples, Victorian socialism was the offshoot of apostates who lost their faith in God, and then relocated their lost faith in the betterment of man.
In America, this carried over into the social gospel.
Likewise, many mainline denominations substitute political activism for evangelism and traditional theology.
The creed of the political left becomes the creed of the religious left. The agenda of the political left because the agenda of the religious left.
They are still missionaries, but their missionary zeal is politicized and secularized.
Left to their own devices, Christians are generally apolitical. They only mobilize on the political front when they feel that their faith and their traditional lifestyle is under attack.
2.In addition, unless the Christian home in which an apostate was raised resembles something out of Carrie, a Christian upbringing can have the ironic effect of giving him a rose-tinted view of the human condition.
For while the child hears about original sin and total depravity from the pulpit, his actual experience is far more positive.
And that’s because he’s led a sheltered life and a charmed existence within the walled garden of a Christian family or local church.
So, even after he leaves the faith, he is still basking in the afterglow of his formative experience.
Likewise, it takes a long time for a “post-Christian” culture to fully revert to its pre-Christian bestiality.
If, by contrast, he had grown upon in Sodom and Gomorrah, he would be thoroughly corrupt.
3. So the apostate is a mutt: one part Christian to two parts atheism. He doesn’t exemplify the character of purebred infidelity.
Rather, the repercussions of his secular outlook are often diluted by the lingering influence of his early, Christian conditioning.
4. And this inconsistency is an effect of common grace. The people of God benefit from the fact that many unbelievers are better than their creed. Their inconsistency is a blessed inconsistency. God has frozen them in place before their metamorphosis was complete. Before they reach the end-stage of infidelity.
So it can, in a sense, be hazardous for a Christian to point out the inconsistencies in secular ethics. For an unbeliever can resolve the tension in either of two directions—one more benign, but the other more malign.