Your point would be brilliant if mormonISM where in fact Christian.
My point was that most denominations view, if grudgingly, other denominations as some degree of “non Christian”. Witness a recent FR thread notes the Pope declaring unification of Christianity per se would require “conversion” of non-Catholics thereto.
My point likewise can be expanded to include Judaism, Buddhism, Hinduism, and other widely respected religions who in no way consider others an alternate true path. They may have grave doctrinal differences, but they can at least function together in a polite & respectful manner on the political stage.
Wherever you place Mormonism on the religious spectrum, a believer thereof can function in a respectful manner in politics.