Good point. Wouldn't a god be powerful enough to convince an unbeliever regardless of their scepticism? Why would it matter that we have to be "open"?
At the age of five, Skagra decided emphatically that God did not exist. This revelation tends to make most people in the universe who have it react in one of two ways - with relief or with despair. Only Skagra responded to it by thinking, 'Wait a second. That means there's a situation vacant.'