I accept that Liz Trotta has apologized, but I still need to understand something. . .

So I have one more question Liz Trotta or her employers over at Fox News:

What exactly if *supposed* to be funny about the image of Osama bin Laden, and Barak Obama dead together?

I get "bomb-bomb-bomb, bomb-bomb Iran", it sounded like a song! I see why it was funny, har har.

But wtf?
Can we get Liz or the folks over at Fox News to explain why that's funny. . . why "knocking off Obama" is a joke to them?