Thanks to Ronald Reagan's signature on EMTALA in 1986, hospitals must by law provide service to anyone, regardless of ability to pay among other things.
It turns out that the costs of this beneficence have indeed grown into a big problem, but it is nowhere near as big a problem as advocates of ObamaCare would like to make out.
Here's the government's best estimate of the problem, from the Congressional Budget Office, which everyone has known about since 2008 (italics added):
"A recent study by Hadley and others, which used that analytic approach, examined a sample of medical claims for uninsured individuals and projected that they would receive about $28 billion in uncompensated care in 2008. That study also examined cost reports from hospitals and a survey of doctors and generated a different estimate: The gross costs of providing uncompensated care would be about $43 billion in 2008, of which $35 billion would come from hospitals and $8 billion from doctors. Total spending on hospital care in 2008 is estimated to be about $750 billion, so those figures would imply that uncompensated care accounts for about 5 percent of hospital revenues, on average. Those findings are consistent with CBO’s analysis of uncompensated hospital care (cited above), which found that a sample of for-profit and nonprofit hospitals incurred costs for such care that averaged between 4 percent and 5 percent of their operating revenues."
So there you have it. The government has known all along that this has been a problem in the neighborhood of 5 percent of the gross costs of care overall, yet it is preparing under ObamaCare to spend $200 billion annually to bring in the uninsured, almost 5 times as much as the problem warrants, wrecking insurance for everyone else in the process.