In your opinion what causes christians to believe in Jesus

[Sheldon]

Evidence is simply the available body of facts or information, indicating whether a belief or proposition is true or valid. Whether that evidence is sufficient on any given proposition is another matter, but the more that evidence is interpreted subjectively, the less reliable it becomes, the more objective it is, the more reliable it becomes.

I don't think it's true to say that evidence is the available body of facts or information. 

So you were using semantics to remove the word indicate form the dictionary definition I quoted and linked, to use sophistry, so you could have a gotcha moment. Also pretending I had in anyway disputed that facts must necessarily rely on previous knowledge. I have seen creationists for example, interpret evidence from the theory of evolution, and come up with conclusions that are at odds with universal conclusions among elite scientists in that field of study. Now, who do we think is more likely giving a subjective interpretation, and who is following very strict protocols for examining evidence, to remove subjective opinions as far as is possible. 

If you and John want to believe it is the former, then you're of course entitled to, but I cannot concur. 

Why is the only question?

Interpreted and indicate are not necessarily the same thing obviously, and on it's own interpretation could be entirely subjective. This is why john is wrong, as science and its methods are designed specifically to remove just such subjective bias, move the what the evidence indicates as far away from subjective interpretation as possible.