Faith can be based on evidence (I have faith my gf is not cheating on me because it seems to be inconsistent with her character). In this sense, 'faith' is a synonym for 'trust'. Religious faith is a different matter and a different sense of the word, it is strong belief in a religon based on 'spiritual apprehension' rather than evidence. Using faith interchangably in both senses in the same conversation is apt to get confusing.
I'm not anti-Christian. I'm anti-stupid.