To add to Sir82's excellent point and in response to this question:
MeanMrMustard: What exactly is it about the healthcare market that makes it a unique market?
Something called "inelastic demand" puts it in a class of markets that are unique and are not subject to standard supply demand forces. What the law of demand states is that as the cost increases the demand (in quantity) decreases. For inelastic demands, like say, water and healthcare, the demand does not decrease no matter what the quantity or price. I'm dying of thirst, what would I pay for a glass of water to keep me alive? Answer, everything I have.
There is no countervailing force to keep prices low because demand is inflexible to price. I need cancer treatment, what would I pay to keep alive? Answer, everything I have. Demand will not drop as prices rise.
(Not exactly everything I have. I wouldn't leave my family in a bad state. I would rather die. Still, you get the point, I'm sure.)
So, for things like water, utilities, and healthcare we tend to rely on heavy government control. Insurance is, of course, a form of collectivism. If health insurance is only provided to those who have no preexisting conditions and come from low risk groups then, yes, those people will pay relatively little. However, if you must insure the population as a whole, you have to smooth out the peaks and valleys. Normally, additional charges are on those who make poor lifestyle choices (eg.. smoking). But, the price is blindly fixed for the group. The idea is what coverage should a theoretical child have for life not knowing what conditions, social group, education, employment, race, or locale he or she will be born into.
I don't argue with anyone's criticism of the ACA. After following this thread, I'm not informed enough to say it is the answer for my American cousins. However, although I'm free enterprise in many ways, I'll argue till I'm blue for universal healthcare (single payer, private delivery, public delivery, insurance exchanges, and single insurer... whatever gets it done).