I don't.
I was trying to explain to one particular such Christian friend that the problem with religion is that "The fish is the last to know that it lives in water". That is: it seems obvious that "Our religion is the one true religion" only if you hadn't travelled and realised that everyone thinks that, but doesn't agree with you. In a context of a Christian country, a Christian upbringing, and a Christian government, this is not so obvious.
She disagreed, and said very firmly that she does notice such consistent trends. "I would know if I lived in water."
We were in a packed lecture hall. In reply, I said simply:
"Everyone single person in this room is wearing jeans, except me."
For what it's worth, I don't think this is true. There are a good number of places in the world were people of different religous faiths live alongside each other. Sometimes they try and kill each other, but often they can live fairly peacibly. India's a good example (including both the killing and the peacibly part).
Or to put it another way: they all think their shit don't stink. It's even crazier when you break it down into denominations (see: Iran vs Saudi Arabia).
As a field we've gotten a lot of mileage out of deciding that something simply must be true due to the aesthetics of a set of equations, and our heroes (Dirac and his positron, Higgs and his Boson) are people whose faith in their aesthetic judgment was retroactively rewarded by experiment.