I feel prompted to start with the principle of being "born again," because I am confident that there are plenty of misconceptions nonetheless. Jesus explained, "Unless a man is born again, he cannot see the kingdom of God. That which is born of the flesh is flesh, and that which is born of the Spirit is spirit. Do not marvel that I said to you, 'you must be born again.' If I have told you earthly things and you do not believe, how shall you believe if I tell you heavenly things?" Excerpted from John 3:5-12.
This is the principle. I don't see any need to belabor its meaning at this time. Jesus didn't.
What's more important is the truthful, practical implication:
"God did not send his Son into the world to condemn the world, but so that the world might be saved through him. He who believes on Him is not condemned, but he who does not believe is condemned already, because he has not believed in the name of the only-begotten Son of God. And this is the condemnation, that the Light has come into the world, and men loved darkness rather than the Light, because their deeds were evil." John 3:17-19.
While Jesus's proclamations offend many, they should not. Jesus does not make the claims to be offensive. In fact, he prefaces all talk of condemnation with a proclamation that His purpose in coming to the world was to save the world. Condemnation is simply the condition in which mankind lives, absent Jesus's salvation. The weight of the New Testament demonstrates not condemnation, but the love and hope that Jesus offers. For those who don't believe that Jesus is capable of saving the world (or that the world needs saving), it should matter very little that Jesus also claims that rejection of salvation is condemnation. If Jesus is wrong and we don't really need saving, what does it matter that Jesus also says that our natural, human inclination is condemnation?
Jesus simply makes a logical, rational statement that has one of two logical consequences: he is either right, or he is wrong. No need to be offended. If he is right, what he's saying has significant, life-altering consequences. If he is wrong, he (and his claims) are not to be any more feared than the boogeyman.
A lot of people in the western world don't like Christians.
One thought is that people are offended because Christians are "exclusive." Jesus says that he is THE way, THE truth, and THE life, and no one gets to the Father but through Jesus. If someone doesn't believe this, why would they care about being included by the Christian group? Every religion claims to have exclusive answers about life's greatest questions. Intellectually, it is far easier to accept the argument of the person who hates all religions (another question entirely). If you think about it, what is astounding is that secular westerners don't seem to hate other religions. They all seem to hate Jesus. So I wonder what there is to this guy, Jesus Christ.
Another thought is that Christianity is offensive because Christians do have a natural, human tendency to do the condemning. One problem is that they don't "speak the truth in love." While this may be somewhat true (no one likes an abrasive, loveless antagonist), it's not the condemnation of that gets people offended. Again, every religion has some doctrine explaining salvation and condemnation. At the heart of Christian offense is the authority by which the Christian speaks of condemnation.
Ultimately, people don't like Christians because Jesus does have the authority to save the world, Jesus is correct when he says that the world is otherwise condemned, Jesus's claims have ultimate consequences regarding how we should and should not live, and Christians willingly accept this and believe it.