tldr; (exactly from the article): "The driving force behind all this, according to Aetna, is the way hospitals and the government do business. The rates that insurance companies pay are negotiated based on what they believe a hospital’s true costs are. But then those rates are jacked up an average of 30% to 50% to make up for money that hospitals lose in treating patients who don’t have private insurance - which is the majority of them. So to make up the difference, they overcharge patients who are insured. This practice is called cost-shifting. In a typical hospital, upward of half the patients are covered by Medicare and Medicaid - neither of which pays the full cost of treatment. Another 10% to 15% of patients are uninsured; maybe they can afford to pay, but more likely they’re broke and can’t cover their bills either. Any profit the hospital makes must come out of the remaining 40% - patients with private insurance."

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Considering that the per capita medical costs in the US are about twice that of the other OECD countries, clearly there's more than just cost-shifting going on.

Whatever your views, as a matter of law (well before "ObamaCare") we are still going to subsidize medical care for the old, poor, children, and the irresponsible through our taxes and direct payments.