For people encouraged to think with their heart, emotional responses seem more 'real' than intellectual ones. The Jesus idea plays upon this trait beautifully.
Who can resist the idea of a loving, all powerful invisible friend who wants to give you a place in paradise?
The beauty of this model is it can't be debunked by any evidence or argument. perfectly intelligent people are able to accept bizarre ideas as reasonable because to not do so would deny the wizards love and the hope that implies. Evidence of error in books once thought to be the divine unalterable word of god means the fault is in our interpretation. Any contradictions inherant in the texts or actions reported there by the father wizard that would be considered evil in ANY other context as we understand it (like slaughtering Egytpian women and children)merely means 'he' works in ways we can't understand.
Interpretations that were the dominant ones for most of the history of Xtianity have gone by the board until the religious concepts held by a lot of Xtians in 2009 would be heresy to most Xtians who have ever lived. eg. getting into heaven without accepting Jesus as Lord? Jesus is too nice to not let decent Muslims in now it seems.
Ideas that would have had people burned at the stake 300 years ago for holding are part of mainstream Xtian belief now.. don't believe in the virgin birth or the miracles?.. no problem!
The age of media has taken the Jesus idea to massive parts of the globe, and the beautiful lie continues to be one of the most sucessful memes extant. No matter what cards science and reason holds, nothing trumps the Jesus ace. It's the perfect con trick.