Republicans simply don't care about looking stupid or hypocritical -- even in the face of incontrovertible evidence.
To wit. The hubbub over Rep. Grayson's "die quickly" remark. The Republicans simply don't care that they themselves have spent the last two months (if not more) telling us that President Obama is going to kill old people. It doesn't matter to them. They just plow forward with whatever loud noises pop into their walnut brains.
If I post on this blog that using the word "crazy" is uncivilized discourse, I naturally would look like an idiot because I write about crazy wingnuts almost every damn day. And if someone points it out, I would consequently feel stupid and embarrassed and a retraction would be in order.
But the Republicans have somehow found a way to shield themselves from shame. There's a doctoral thesis here, I think.