What the JWs have told us about Christendom is NOT always true. Of course, just like the JWs, there are bad apples in every barrel. But almost every church (religion) I've been to, has expressed they realize they cannot ask people to adhere/believe 100%. Rarely is there someone that believes 100% of the religion's doctrine. And if they don't, they aren't shunned for it.
Andi, you are so at the door on this! The churches of Christendom even says that any group that tells you they and they alone have the only truth about God is being decietful. Even the apostles had differences of belief so it should be expected. Unity in faith in Jesus is not the same as conforming to every whim of a religion that is apt to change without a moment's notice.