My father is a physician in a public health hospital in the US. He works long, difficult days long, running from one emergency to another. He tells me most patients feel little responsibility for their health. Many make highly questionable lifestyle decisions which result in crises for which they feel no responsibility. They generally see no reason to change their behavior once the crisis has passed. The state picks up the bill for the massive health care charges they run up. No one is ever turned away.
Incidentally, he works in Louisiana, whose summers consist of exactly the sort of weather that killed France's thousands. I need not add that thousands do not die each year, alone and neglected, in Louisiana's summer heat.
On a related note, he has patients who can afford private health insurance but see little point in paying for it when state-funded care is so readily available.
I experienced the national health care system in Canada. The quality of health care in the United States is significantly better. And for the poor there are many options. When I had a health emergency in graduate school in the United States, for which the bill would have been impossible for me to pay, the private hospital that treated me picked up part of the bill because my income was low. They took excellent care of me, knowing before my treatment began that I would not pay the entire bill. My physician was the best oncologist in the city.