We can break that down.
My gut says the ego, the arrogance, of the millennial staffers who think they know so much more than the graying middle age staffers, the arrogance of the unionized bureaucrats, the ego and arrogance of "The One", said "We won, we know what we are doing."
But then there is the potential pragmatic side, which realizes it will never be held accountable in the media, can get away with literally anything. They would build ObamaCare and then destroy it with a Cloward-Piven play in order to bring about single-payer.
Either is equally possible.
Then there is the possibility that Obamacare has been steadily hemorrhaging support since its passage and they had a real fear that if they didn’t rush it into implementation, the public clamor for its repeal would increase to a fevered pitch.
Or that there are real legal challenges working their way through the courts which threaten portions of the act, but once in place, Congress would be pressured to amend the law to comply.
Actually, even though SCOTUS upheld the mandate, their striking down the state required Medicaid expansion will add billions of $$$ to the estimated 10 year cost. Millions make too much to qualify for Medicaid, yet too little to afford insurance. They have no choice but to pay the penalty. So millions will still be left without insurance and taxpayers will pick up the tab for their emergency room visits.