More seriously, rewarding holding the budget (or debt limit) hostage just makes it rewarding to use such tactics in the future.
Plus, despite having a jaundiced view of the ACA (ObamaCare), only 33 percent of registered voters believe that the health law should be repealed, delayed, or defunded. Granted, that group will only blame the Republicans a little more they blame Obama, but still. So, the representatives causing the government shutdown are a minority of the House, don't reflect the will of a majority of people, are blocking a lawfully passed, Supreme Court upheld law in a way that will damage the economy (and a large number of ordinary people). How is that morally defensible?
The individual provisions of the ACA are mostly very popular, with the individual mandate being the most unpopular part. Unfortunately, you need the larger pool of folks (in particular, healthy folks) to enable those other provisions (no lifetime limits, can't be denied for pre-existing conditions, etc). It's certainly not an ideal law by any means, but it seems like an incremental improvement over what we had.
I'm sure it will need to be tuned over time, but it's hardly the end of the world or rampant socialism— there's not even a single payer option, which I would have liked. Making people contribute to their health insurance (or, effectively, giving people a tax break if they do) is not the end of the free world.