Ahh infinite regress. One of the few places special pleading cannot hide. It has the effect of pushing the God hypothesis into unfalsifiable territory. It is the place beyond which the goalposts cannot be moved, and so the invocation of faith becomes a necessity.
IOW, it's a good questions to ask, but it will always get you the faith card in return if you push it. It's what some call fleeing from fact. People start out talking about evidence (the world is amazing/complicated) but when that evidence is questioned and indefensible, they resort to feelings. When the subject is god, the retreat is to faith. With other beliefs, like say psychics, the retreat is to opinion. They start by saying there is evidence for psychics, and when you show the evidence to be flawed, well that's just your opinion. Suddenly we aren't talking about facts any longer.
It's something all humans are prone to do, especially if the belief is closely tied to their identity.