We believe that Jesus' followers have never managed to live up to His example, but that does not invalidate His message.
One of the key aspects of the Christian faith is that we believe Jesus was - and still is - perfect. His followers are not, and (should!) never claim to be.
Of course, we seek to follow His example. We believe that He helps, guides and strengthens us. As we grow spiritually, we become better people. But none of this prevents us from falling short of His standard.
More than this, many people who follow Jesus, or who claim to follow Him, have seriously misunderstood Him and the nature of His teaching. Nobody who understands the Sermon on the Mount - for example - can possibly be involved in something like the Crusades and believe that such an activity is compatible with following Jesus.
At times, the 'official' Christian churches have seriously failed to teach abouut Jesus, or have mis-represented Him. Like any institution, the church can fail and become corrupt.
But sad and depressing though this may be, the failures of the people who followed Jesus do not invalidate His message or ministry. After all, we do not imagine that, if a Physicist leads an immoral life, that this reflects on Isaac Newton or throws the law of gravity into doubt. The followers are less than the master. It would be strange if this were not so.
It is interesting to ponder why this is an issue.
People certainly expect the followers of Jesus to be leading lives of greater moral purity than the general population. And this is not unreasonable in itself. But there seems to be a great gulf between the feelings and words of people in the Church, and what the people outside the Church pick up.
People in the Church are very often terribly aware of their moral failures and weaknesses: they know that they should be good, and deeply regret the fact that they are not - while (it seems to me) they often do far better than they realise. But people outside the Church seem to hear them claiming to be very good, and denounce them as hypocrites when they fail to live up to the standard of perfection they set for themselves.
Which is not to deny that sometimes prominent Christians are dreadfully hypocritical. They are, after all, human.
But the fact remains: the Church is a sanctuary for those who know they are sick, who recognise they need help. It is not, and never claims to be, a place for the perfect to meet each other.
Christians do bad and stupid things, just like everyone else. But the surprising thing is the amount of grace and love and forgiveness you can generally find among these weak and fallible human beings.
Jesus said that people will recognise His followers, not by their perfection or holiness, but by the love they have for one another. And in every church I have visited, that unexpected love can be found.
I believe I have already covered the objections above. Do let me know if you can think of any others.
The only alternative - the claim that the failure of Jesus' followers to live up to the example He gave somehow invalidates His message - has never been seriously presented, as far as I am aware.