David French has some observations about the hesitance of Christians to explicitly discuss faith in debates with non-believers:
One has to swim in Evangelical waters to understand how completely we’ve accepted the veracity of the bad faith critiques from the secular Left. We run around wringing our hands, saying things like “we’ve got to make sure we care about children as much after they’re born as we do before” when we’ve never, ever devoted even a fraction of the resources to ending abortion that we do to ending poverty. We tell ourselves not to “obsess” over same-sex marriage and abortion when those topics are rarely (if ever) addressed from the pulpit and again receive only the smallest fractions of Evangelical dollars and volunteer hours. As Jonah so eloquently stated, we’re not the aggressors in the culture war.
Oh, and we are also convinced that people will love us more if we talk about Christ less and are just the nicest, most service-oriented people in the room.
In other words, Christian, shut up and serve soup to the poor.
…
The “concern troll” against Christians translates like this: “You should talk about life less if you want people to be more pro-life. You should use the Bible less if you want people to respect Scripture. People will like Christ more if they never hear about him.”
Over time, and with the benefit of experience, I came to utterly reject the notion that I should only talk about cultural, economic, or political issues without reference to the Bible.
… those people who so often assure you that the Bible isn’t persuasive usually have no idea what the Bible says about virtually anything. Biblical illiteracy is a culture-wide problem, and confident assertions that the Bible has nothing meaningful to say on any given issue are typically the confident assertions of the ignorant.