I lost count decades ago on how many times I’ve heard variations of the “I can’t believe in Christianity because most Christians are a bunch of hypocrites” argument against Christianity… and it still mystifies me how many people view it not as an emotinal objection, but a logically valid argument!
As an observation, “Many (perhaps most) self-described Christians are hypocritical” the statement is sadly accurate. The main reason for this is that the majority of such people, at least in North America, are NOT disciples and followers of the Christ but only ‘cultural christians’.
As an argument against Christianity, though, it is both nonsensical and illogical.
An illustration of how nonsensical the argument is also shows how it is illogical. Let’s suppose that you are approached as you approach an apartment house on your way to visit a friend by a man you recognize from newspaper photos. He is a convicted mass murderer and former fireman who has recently escaped from prison, leaving a note saying that he would never set another fire, but intended to kill as many as possible by drowning. Running past you at top speed, he yells ‘Don’t go in there, the whole place is on fire!” Looking at the building, you see flames and smoke coming out of many of the windows.
Looking behind you, you notice that the man has stopped to light a paper recycle bin on fire. You therefore conclude that the man is a hypocrite, and continue into the apartment house to visit your friend as the first fire trucks arrive on scene.
I give this ridiculous story to illustrate that just because the messinger may not live in accordance with the message, the message itself must stand or fall on its’ own merits. For a more detailed examination of this topic, see articles at Thoughtful Christianity, Christian Answers. and this article by Brad White.