Buy the Premise, Buy the Gag

You know what's wrong with me? (I mean aside from dressing badly, of course) I just spent a considerable amount of my work morning hectoring poor WAMK for retweeting this.

PS to today - You know it's election season when Obama spends a Sunday at church instead of a golf course.
— Emily Miller (@EmilyMiller) August 20, 2012

My first assumption was that the gag is that Obama fellah is lazy, just like all...Democrats. But after an awful lot of back 'n' forth, I think we've concluded that it's funny because that Obama fellah isn't a religious guy, that he PRETENDS to be religious only when he's campaigning.

I think that's great because it means that Emily Miller (and WAMK) never believed the "Secret Muslim" thing, or the nonsense about Rev. Wright. Obama wasn't influenced by those guys! He just wanted to play golf! People who buy that stuff are idiots!

Probably WAMK will take offense to that interpretation but he has been pretty close to the vest with why he thinks the line IS funny. "It's funny because it just IS," he almost said, though he hasn't quite even gone that far. Without some underlying premise, it's not a very funny line. I'm open to some sensible explaination of what the premise is. Do you think the tweet is funny? Why?