Poor representation by Christians often confirms unbelief in the world. Why? Is it because the gospel is weak? Hardly. But humans are, and I don't care which way you try to skin them, the saints are still human. But really, isn't their misbehavior a bad excuse to use for unbelief? Is truth any less relevant because some of its confessed adherents can't walk the walk? Do you make your decision to accept truth or not based on the behavior of others? That's some pretty sorry criteria. If a science professor embarrassed you before the whole class, would you throw out your belief in thermodynamics, quantum mechanics, and the rest? Not if you believe it for the truth that it is.
Have we forgotten that people lie? "The heart is deceitful above all things and desperately wicked. Who can know it?" (Jer 17:9) Lies are everywhere. That's really what it is when Christians don't practice what they preach. So do you throw out the truth of God because of a lie? Let someone control what you believe? If liars control your belief system, who are you going to end up believing? Who's the father of lies? Yeah. Pretty intense. Now the purpose of this is by no means to excuse the lame failures of Christians, because they are inexcusable. But we gotta think! Don't look to people. They will always let you down.
So theoretically, everyone should bypass the yardstick of the fake Christian and look straight to Jesus for their measurements. The reality is, most people will never do that. There will always be the skeptic and the scoffer. It has always been that way, always will. The Bible predicts it, especially in these last days. (2 Pet 3:3) It also predicts the failures of professed Christians. People have a form of godliness but deny its power to change their lives. (2 Tim 3:5) So they keep living like everyone else, happily wallowing in the sty. It's such a tragedy.
The pleasures of sin have always been popular. Partly because they're tangible, here and now, and partly because Satan is such a damned good salesman--not because he has a better pitch, but cause he controls the majority of the advertising. So the hypocrites think they can have the best of both worlds, while the skeptics use hypocrisy as an excuse to continue ignoring truth while enjoying the scintillating pleasures of the world. It's so cheap though, and they never find real satisfaction.
What it really comes down to is a matter of love. God's love for the unbeliever is still so incredibly real. And if they would start to see that and keep looking, they soon wouldn't be able to
stop believing. It's all about focus. I guess that's why hypocritical Christians are such a stumbling block; because so many of us look at ourselves or others instead of to Christ. That's why a Christian may be the only Jesus a person ever sees, and if they aren't showing the love, someone may never see it. And if they never see it, they aren't going to believe it. (If only they'd look to the Source!) So what can we do? We gotta be looking up. That's where the power is, that's where the love is, that's where it all is. And by beholding we become changed. (1 Cor 2:18) Then those skeptics won't be able to look anywhere but. :)