They figure the birth certificate thing must be wearing out, so the wingnuts needed another fantasy based on a tiny shred of reality they could scream about to their followers.
The great thing about right wingnut media is that their followers will never do any fact checking or have the slightest doubt it's the truth - because it's what they want to hear. What they want to hear is Truth, and anyone providing actual facts is "just trying to do a cover-up".