Hmm I am just reading this now, I can't believe she even went and saw the movie with you. And if she did and based on what she has said, I am wondering if she is struggling with her own sexuality, is that a possibility?
Otherwise I don't see where her anger is coming from?
But I think we have to be careful and not think that her feelings are the feelings of all Christians. I am Catholic, I believe that Jesus did walk on water, but I am not a nut!
She doesn't follow the teachings of Christ, not even close, and she can call herself what ever she likes, but her beliefs are not Christian.
I don't know what your relationship is with her otherwise, but personally I wouldn't have her as a friend. My SIL's are my friends, they are people I love and want to be around.
(((HUGS))))