You should not decide whether you believe or disbelieve anything until you have enough information to make that decision. When someone wants to know if you believe something, your answer doesn't have to be only yes or no. A perfectly good answer is that you don't have enough information to make that decision. You can also answer that you don't want or need to make that decision. So when someone says, "Either you believe it or you don't." that's equivalent to saying, "Either you're for something or you're against it." and in both cases their statements are false. There are even more responses to such statements - for example, "I reserve the right NOT to make that decision" or "I don't care."