As it stands now, the current healthcare situation in US is flawed. Healthcare coverage is not required, yet hospitals cannot turn down people at the ER. This particular situation gives rise to Tragedy of the Commons, specifically that there are people who can afford health coverage that instead choose to allocate that money for something else, yet when the a medical emergency arises, the hospital must absorb their financial gamble. And of course, the result of that is the unfair financial burden on those that "play fair" and have insurance, since the hospitals are forced to raise prices to offset the losses from the uninsured ER patients.
To avoid this freeloader scenario, we have two options: either turn down people at the ER, or make healthcare coverage mandatory. Since the first option is unconscionable in a civilized society, that leaves us only with one rational choice. As to whether the healthcare should be provided by regulated private insurance companies or by the government is a whole different debate altogether.