There is this rule of logic that xians ignore called the anthropic principle. Basically it points out that in order to ask a question things have to be the way they are. So to ask why the universe is finely tuned is illogical as we wouldnt be able to ask the question if it wasnt. The same applies to the question 'why did the first xians believe jebus rose from the dead?' If they didnt believe that then we wouldnt be asking the question. All the following also commit the anthropic principle:
-why did people write the bible?
-how do we know that murder is wrong?
-why did the big bang happen
-why do so many people believe in sky daddies?
Each one of those questions can be answered by pointing out that we wouldnt be able to ask the question if it wasnt the case. I think you xians are going to have to come up with some more arguments that dont commit the anthropic principle.