Let the republicans construct a separate bill that defunds and delays and repeals the ACA, put it through the legislative process, and have it pass both houses and be signed by the president. Oh wait, they have tried this and failed, repeatedly. They've also challenged the constitutionality and failed, repeatedly (looking at the piecemeal challenges of one overall effort). So now they are holding the solvency of our government, the pay of millions of employees, and quite frankly, the entire world market hostage until the president caves on an already-funded-and-has-nothing-to-do-with-the-continuing-resolution health care plan.
That's why.
EDIT: I've lost 10% of the value of my stock holdings in the last two days for no other reason than the markets are "jittery" from this. Wee wee wee, first world problems, I know, but seriously, real people are affected by this bullshit they are pulling.
I'll say it again, this is going to blow up in their faces. The dems are going to make so much hay out of this that the republicans will be known as the junior party for some time. I think they may even splinter, with the extreme wing forming an official Tea Party (such a gay name), the libertarians throwing up their hands and walking out, and the moderate, business republicans being left gutted.