Because the poor should pull themselves up by their bootstraps or learn their place in the world.
/Republican
Anyways, some would say costs, but the ones who cry loudest about costs in America (at least the ones in nationally elected offices) don't give a damn about cost and want tax cuts tax cuts tax cuts while expecting to pay down the deficit while allowing the rich to hoard/not invest their money into the economy (whether they should do that or not is debatable but if you care so much about deficits it would be in your interest to get money to flow into the system in one of the few places where there's money left, especially in a country with so much wealth disparity that 2% have 85-95% of the wealth).
I'm also kinda pissed at the Democrat's healthcare bill. First they threw out the really good option to compromise with Republicans (single payer), then Obama did a backroom deal with insurance companies (there goes the public option), then we get this really reallly reallllllllllyyyyyyyy conservative healthcare bill (basically the same thing Republicans wanted to pass in 1994) and people are still like "hurr durr socialism". That and people whining about being forced to buy health insurance because they apparently want everybody else to foot their bill out of their taxes when they can't pay for it (one of the things they attack healthcare reform proponents for no less), not to mention the individual mandate was a Republican ideal.
So as for America the real reasons are:
Red baiting
Ignorance
Apathy/Sociopathy by corrupt or indifferent politicians
Added note: If it's an emergency, EMTALA makes sure they go to an emergency room, but if they can't pay for it, you eventually foot the medical bills out of your taxes anyways. HCR attempts to streamline that cost and makes things more efficient.
