Congressional members and staffers are realizing what Obamacare means for them, don't much like it, and are attempting to exempt themselves from the law. From POLITICO (emphasis mine):
There is concern in some quarters that the provision requiring lawmakers and staffers to join the exchanges, if it isn’t revised, could lead to a “brain drain” on Capitol Hill, as several sources close to the talks put it.
The problem stems from whether members and aides set to enter the exchanges would have their health insurance premiums subsidized by their employer — in this case, the federal government. If not, aides and lawmakers in both parties fear that staffers — especially low-paid junior aides — could be hit with thousands of dollars in new health care costs, prompting them to seek jobs elsewhere. Older, more senior staffers could also retire or jump to the private sector rather than face a big financial penalty.
Plus, lawmakers — especially those with long careers in public service and smaller bank accounts — are also concerned about the hit to their own wallets.