Being Hypocritical About A Truth Does Not Invalidate The Truth.
Do a Christian's actions change the truth?
Let's say I was standing in front of you smoking a cigarette and said, "Smoking is bad for you! You ought not to smoke."
Will you say to me, "You are a hypocrite and therefore what you are saying must be false. Therefore, smoking must be good for you." That is absurd.
However, rational people will actually say, "Christians are hypocrites and therefore what they are saying must be false. Therefore, there is no God."
That is an error in logic called a non sequitur. It is an inference or conclusion that does not follow from the premises or evidence; a statement that does not follow logically from what preceded it.
Are Christians hypocrites? If a Christian says to you, "You should be like me; a perfect person who does no wrong." Then yes, that Christian is a hypocrite. However, I have yet to hear any Christian, that is, a follower of Christ, make such a statement.
What Christians are most often heard saying is this, "You ought not to sin." And this means different things depending on to whom it's directed.
What an atheist thinks he hears is this: "You are a bad person unlike me who is a good person." If this was what was truly said then hypocrite is a worthy label.
This statement "You ought not to sin", however, is usually, or at least should be, directed only to Christians. When a Christian says, "You ought not to sin", he means: You ought to obey God's laws because He loves you, He knows what's best for you, and because of what He did for you your desire should be to obey Him.
Why would I say that the moral imperative that one "ought not to sin" be directed only towards Christians? Because there is no reason to tell an atheist he ought to act according to God's laws. What would be the point? Biblically speaking an atheist's actions, whether moral or immoral, will have the same result: eternal separation from God. So telling an atheist he ought to be good does nothing for his eternal soul.
So while it is understandable to say, "You ought not to sin" to a Christian, to an atheist it would be better to explain to them how Jesus died for our sins and that without Him we are all sinners separated from God.
Are Christians hypocrites? One of the greatest apostles of the Bible writes this,
Rom 7:18,19 "For I know that in me (that is, in my flesh,) dwelleth no good thing: for to will is present with me; but how to perform that which is good I find not. For the good that I would I do not: but the evil which I would not, that I do."
For followers of Jesus Christ, who understand that man is a fallen and sinful creature, battling the flesh is a moment-by-moment struggle. "We're not perfect, just forgiven" some say.
However, regardless of the actions of those claiming association with God, God and His truth do not change. Malachi 3:6 "For I am the LORD, I change not."