"I think it a little unfair to pick on Mormonism as any more nutty than Catholicism. Simply because of age?"
Yes, age has a lot to do with it. It's one thing for ancient, cherished myths to be passed down and modified century after century. It's quite another to fabricate an entire book out of whole cloth, claiming that an angel pointed you to some ancient plates that you managed to translate with the aid of some magical instruments. Of course, none of it makes much sense, but at least Catholics can admire a long history of myth-making, which started back when the term "myth" didn't have the connotation of being anti-Enlightenment, anti-rational. What's to admire in the myths of the Mormon church, which were invented by a small handful of Anglo-American men within the last couple of hundred years? (Not to mention the bit about the indigenous peoples of the Americas being cursed with dark pigmentation because of their wickedness.)