We could settle on a logic that includes some of these unfalsifiable aspects as axioms or rules. A useful logic doesn't necessarily imply unfalsifiability in the sense of physical experiment. It could very well contain axioms we all reasonably agree on, like "I exist." The problem with Christianity is not that it makes unfalsifiability claims, it's that it includes all-encompassing statements like "god is everything", "god does everything". How does this tree grow? God grows the tree. How is it that I age? God ages me. How come it appears the tree grows according to laws? God made the laws--or more perversely--god made me think there are laws. This perspective is useless for fuethering knowledge. In fact it attacks knowledge by trivializing it. It unversally wraps every possible statement in "god". My stance toward christians is they may as well keep all the god stuff to themselves because it adds absolutely nothing to the conversation.
I totally agree that adopting Christianity as an axiom makes no sense. However, "existence has some greater purpose or meaning" is a not-entirely-unreasonable axiom for someone to adopt, and I think someone could get from there to Christianity as a conclusion.
