Why are Democrats worried about NOT pressing ahead with healthcare reform before the new senator from Mass. is seated?

I cannot believe how accommodating the Dems are on this. Does no one remember just a few months ago how Republicans threw everything they could, including the kitchen sink, in order to NOT seat Al Franken as a senator from Minnesota, after it was very clear that Franken had won the election? And Republicans were very clear on their motivation. They were doing everything they could so the Dems would NOT have that mythical 60 vote super-majority that could pass healthcare reform. But now, we are all worried about subverting "the will of the people of Massachusetts" if the Dems try to push something through at the last minute?

Man, the Democrats are pissing me off. Yes, there are fighters within the party, such as Alan Greyson from Florida. But, taken as a whole, the Democratic Party comes off as scared of its own shadow.