I totally see your point. Really, as a mature Christian, it comes down to faith and your interactions with God. Like in the movie "Contact" no one can prove or disprove my belief that Jesus Christ is God or that God exists. I just know that He does because I have experienced His love for me.
But I sure am glad that I am not a Morman, because I would have a hard time with not having any historical evidence of my faith.
And I sure am glad that I am not a member of the Watchtower or of the nation of Islam , or that my Christian beliefs are not just a religion. Because I would never know if I had done enough to earn God's love.
And I am also glad that I am not an athiest because a life without love or meaning to me is not worth living.
Finally, its pretty sick (I'll admit it) and I know that the only reason I get to go experience God's love is because of Christ's death for me, but I am sure glad that there will be judgement for those who were dictators and those who got away with terrible crimes, because ying and yang and good karma and bad karma just don't always work. SOmetimes the jerk gets the glory and the hero is tortured unto death.
Pretty much the book of Romans is the reason I am a Chrisitian - in faith - not religiously. Because I know that my heart is evil and I know that I need direction. I also know that no human being can love me the way God does.
So, I agree with you that it is about faith. But not just blind faith. Other belief systems - or lack of belief systems - just don't seem to incorporate unconditional love. ANd that's what I experience through GOd - and I can't prove that to you - I can only love the way God loves me.