I'm not religious but I want to make an argument that happens to support Christianity, because, admittedly, what they say is valid. Within the context of Christianity, belief is a choice, and anyone can choose to believe.
Let's use the good old Santa argument: "Can you make yourself believe in Santa after being presented with overwhelming evidence to the contrary? No. Therefore belief is not a choice." My counter argument: you can freely at any time *assume* that Santa is real and assume all that applies as a result of Santa being real. In other words, you can choose to play along. This is very core to how we conduct scientific experiments. For example, you can leave out milk and cookies