You'll note almost never is a black man mocked by white comedians, anywhere. They avoid it like the plague, terrified of being called racist.

Via American Digest to "Word around the net."

Why no mockery of Obama by TV comics?

...they're afraid to mock a black president. You'll note almost never is a black man mocked by white comedians, anywhere. They avoid it like the plague, terrified of being called racist. If you portray him as being arrogant, someone will cry they are saying he's "uppity." If you portray him as ignorant or hapless, someone will cry they are saying blacks are stupid. Just about anything that could possibly be taken as negative is used as proof of racism by the grievance mongers.

They need to appear better than those who would say such a thing to their friends and coworkers. The color of his skin trumps the content of his character for these oh-so tolerant people.

But second, and more importantly, they're following the same pattern as Congressional Black Caucus leader Emmanuel Cleaver: they don't want to hurt their leftist hero. Sure, the hero part is starting to fade away, but he's still the great left hope, their last bastion against the horror of Republicans in power. Weaken him and they might come back, and that's simply an evil beyond imagining.

...

President Obama's fragile, narcissistic, in over his head persona is just too weak to sustain any real mockery. That's why the "celebrity candidate" ad that McCain ran in 2008 was so powerful, and the Obama team had no answer for it. The man is overly ripe for mockery, and ultimately that's why they lay off: he's such a fat target it would only hurt their cause.

Quick summary: (1)they're racists and (2) bees don't sting each other.