It is trivially true that if two statements contradict, whether in religion or elsewhere, one statement is true and one is false.
What we do about that disagreement can be far from trivial. What people do about that disagreement is another matter. In America, we disagree about politics. What we do about it is that we hold elections for President every four years and make orderly transitions from one administration to another. In other countries they do it differently. They kill one another to get control of the government. It's not the disagreement, it's what we do about the disagreement, that matters.