They really are scared of the black guy.
Would you want to run against the guy who made a fool of Donald Trump and the birthers (er, well, bigger than what they already were) not to mention the guy who got Osama bin Laden? After what happened in NY-26, would you want to be on the side that defends The Road to Prosperity/killing Medicare and busting up unions? Or how are they going to defend their pledge to create jobs and reduce the debt when all they've done is defund Planned Parenthood?
Basically, none of them can defeat Obama. And what happened in NY-26, many of them are probably fearing that Pelosi will retake the gavel in 2012. The end.