Undoubtedly if you are an atheist who actively engages theists in conversations about their religion or beliefs or faith you have heard this. You have heard this as a response to why they believe in their particular god. You are trying to find the reasons for their belief and some bumbling idiot of a theist invokes the faith claim. They do this apparently completely unaware of the other religions out there making faith claims. I mean seriously could they have bothered to hit the on button on their brain before making this statement. Im sorry but this is intellectual dishonesty 101. Let me break this down for you, here I am the atheist listening to all these people tell me what they believe:
Ibn Al-Sharik tells me I must have faith in Allah and the holy koran is gods word and that is what i must have faith in.
David Cohen comes up and tells me I must have faith in good ole' Yahweh and that the Pentateuch lays out gods law for us and I must have faith in this.
Some guy whose name oddly reminds me of a villain from the Children of the Corn series, tells me about John Smith and a little something about magic underwear, and I must have faith in this.
Tom Cruise tells me about Dianetics and e-meters and how I must have faith in them.
Now seriously thinking Christians, are you really going to just say, well it comes down to faith. Don't you see how absurd this is. You can't really be serious with this nonsense can you? It wouldn't even make sense if your faith or no faith was an actual true dichotomy, it makes even less sense when you explore the whole dichotomy of faiths.
Faith does not answer the question: Why do you believe in your god? It avoids the question, its a non answer, its the equivalent of jumping up and down and whining, it is because I say it is.