Wlady, you are quite right that Christians would have a different view of historical fact than somebody like Heather Mac Donald has. If not, there would be no such thing as a non-Christian.
However, if I understand her correctly, her key complaint is that Christians make debate and discussion impossible by involving theological ultimacies. I simply think she is wrong about that.
I can talk about the Virgin Birth and she can make the case against it and I can respond. The fact that we can't wrap up a nice agreement in a paper bag doesn't mean this type of dispute is uniquely intractable. I imagine I could have a similarly unresolvable debate with certain people over affirmative action!