the government is trying to argue that the fact that a citizen is alive requires them to purchase insurance
No it is not, and this is the fundamental failing in your understanding.
It is arguing, that the citizen must purchase insurance if the citizen will end up using health care facilities at some point, whether they think they will need it or not. This applies to most people, that is a fact.
And if they don't have insurance then everyone else has to pay for their treatment.
Someone that is alive but is not going to be using private health care services in the united states has no obligation under the mandate (like say an American citizen living abroad, or a military person etc).
It is the same model as car insurance because, I may think I am a good driver and will not need liability insurance, but it is a virtual certainty that I will at some point if I drive a car. People that are going to need health care services in the United States and are not covered are a serious drain on the system. This requirement is not oppressive or unreasonable. If someone cannot afford insurance, the government will pay for it with a subsidy.























