The rejection state is the default. The becoming a theist later in a different point in time that can come with knowledge, yes, but it doesn't change the fact that before the knowledge of it came, the default state was reining. You asked me about a baby who is essentially a tabula rasa. A tabula rasa will only believe what is in front of them and they naturally reject everything else that isn't until the knowledge of it changes. This event is not retroactive. It only takes place from the point in time where they decide to become theists (if they do).
How do you reject something that you're not aware of? If someone doesn't know that the Detroit Red Wings won the Stanley Cup in 1950, that doesn't mean that they're rejecting that they won it that year.