I see the need for posthumous baptism for Mormonism to internally consistent, but jeez, how stupid do they think God is?
"Well, non-Mormon guy, you didn't follow my rules, plus you weren't a Mormon, so I put you in Hell for the last fifty years... but good news for you, your Mormon descendants baptized you! So up out of Hell you come! Which planet do you want to be God over now?"
Even if Yahweh existed, I don't see Him doing that.