Not to speak for my good FRiend but I would guess the “principles” they could not live with may have been the “lying for the lord” or the supporting a “church” that maligns Christ or defending a “Book” that has been proven to be a fraud, not “scripture”. I am sure the list could go on...
That remark was SO typically "superior mormon" that isn't really worth responding to.
IMO, that is the primary reason that so many find Mitt disgusting...he carries that "I'm so much better than you" attitude into everything he does, including showing it during the debates.
We see it quite often among certain mormons here, especially the resident "scold" who feels free to even scold the site owner from her lofty perch.
One reason I'm happy I don't have to deal with mormons IRL.