It's probably because the Democratic leadership realizes that the only bipartisan agreement is on extending the tax cuts for all Americans, rather just on those who earn less than $250,000.
Congressman Chris Van Hollen -- Nancy Pelosi's assistant -- huffs that he'll be happy to take the issue (i.e., raising taxes only on those earning above $250,000) to the voters. Apparently, Pelosi & Co. are going to try to argue that Republicans held tax cuts for those below $250,000 "hostage" to tax cuts for all.
Good luck with that argument.
First, it wasn't the Republicans who voted to adjourn; they were willing to stay and work. It's the Democrats who've given up and turned tail to run home to try to keep their jobs.
Second, note that Van Hollen's argument implicitly condemns all the moderate Democrats who actually voted with -- and agree with -- Republicans about the danger of raising taxes during an economic downturn. Hope the Democrat leadership has fun arguing against their most vulnerable members.
Third and finally, it's just more of the division and class warfare that has characterized the administration and congressional leadership's remarkable mishandling of the economy. Job-hungry Americans understand that it's "the rich" who create jobs -- if the money they'd use to do it isn't taken away by the government.
What's more, it's a pretty damning indictment of the Democrats' politics of envy and class-hatred: They'd rather raise taxes on struggling members of the American middle-class then extend tax cuts on the "rich" that they so despise.