Nor do you have ammo. You, too, can say nothing, nada, about God's possible nature and existence -- yet for reasons you cannot explain, you do accept his existence. For reasons you also cannot explain, you do not accept the existence of Thor. Equally arbitrary.
He also insists atheists should not disbelieve in any deity as the claim is unfalsifiable, and there is no contrary evidence, which he thinks is needed to justify disbelief. Now leaving aside for the minute that is irrational, as it is an argumentum ad ignorantiam fallacy. He won't tell us if he applies the same rationale to all unfalsifiable claims, you have to wonder why.
Since I treat all unfalsifiable claims the same, and disbelieve them for the same reason, and he endlessly accuses me of bias in my atheism. One assumes he also treats all unfalsifiable claims the same, and believes them all, even contradictory ones. Bias like gravity, can be very unforgiving, especially when you ignore it in yourself, and only see it affecting others.