Yes, I agree Mormon theology is rather odd and I do believe it to be false.
The falsity of their theology has little, if anything, to do with the issues at hand or my post, however.
Mormons are mad at Trump because Trump conducted a slash-and-burn campaign during the primaries.
Trump’s strategy of winning by attacking other Republicans was effective for the primary, but will probably come at a cost going forward as supporters of those other Republicans stay home.
Why would they be mad?
Mitt did exactly the same thing.