It's not hard to understand why other Christians get mad at us when the message they hear is,
"Your beliefs are wrong, and your conversion isn't real."
since we get upset at them when they say the exact same to us.
I think we can believe the first part of that statement and still reject the second part - or, as Joseph Smith once said, I don't think anyone should or will be condemned for erring in doctrine. I believe, as our Article of Faith implies, that we will be judged by the intent of our heart and sincere efforts (for Christians) to "exercise faith in God, the Father, and Jesus, the Christ" - not by the specifics of our understanding of theology and doctrine. In other words, I believe we can be "wrong in our heads" as long as we are "right in our hearts" - even as I believe it is important to try, to the best of our ability, to be right in our heads, as well.
"We claim the privilege of worshiping almighty God according to the dictates of our own conscience, and allow ALL men the same privilege, let them worship how, where or what they may."
I believe we will be judged primarily by how truly we worship according to the dictates of our own conscience - and that God probably sighs in exasperation over our collective inability to be more charitable toward those who worship / believe differently than we do, especially since all of us "see through our glass, darkly".