The bottom earning 25% of Americans have 0 assets and 0 money, so health care is effectively free. Go to a hospital, they must treat you, you can't pay the bill, so it gets written off.
The 26-49th percentile of people who have some money but no insurance are the people screwed by the current system.
So the reason why American's tolerate it.. is it works decently for 75% of the population. And it is hard for 25% of the population to really change anything. And of those, many are young and healthy so they don't really care. So maybe we are talking about 12.5% of the population being actively screwed by the system at any given time...