Helmets, mandatory exercise, and fasting are all things that improve the health of that single individual. In contrast smoking, vaccines, or masks are about externalities. We are more hesitant to regulate something an individual chooses to do if it only affects himself/herself. But the moment your actions have an effect upon me without my consent or a market transaction dictating it, then it is a market failure and a legitimate case for government intervention. Thus, the pointing a gun at people is an apt parallel.

As for your CDC PDF, is your point that there were 131,858 pneumonia deaths in 2014-2015 as a way to make it seem like the COVID-19 death count is in line with that? Because that is just ludicrous

There have been 133K deaths in the US out of 3.05M confirmed cases. Studies on the disease being asymptomatic have found it is asymptomatic around 20% of the time. This was from situations like the aircraft carrier where they tested everyone onboard or sports leagues. Thus, they were testing those entire populations. In both cases, those were some of the healthiest, fittest, youngest people compared to the broader population. Thus, there is no reason to think that they were underestimates of the level of asymptomaticness. But for the sake of demonstration, let's assume that we are undercounting the number of infections by 5X. Thus, there would be 15M people currently infected (as opposed to the 3M confirmed cases).

With that, the disease would have a fatality rate of 133K/15M, which is 0.89%.

While that might seem low, when you combine that with how insanely infectious this disease is (where any reasonable estimate would have this thing going through virtually the entire population without extreme social distancing). Thus, let's assume in a world without masks and social distancing we would have around 200M people infected.

That would be 1.78M deaths. That is more than the entire death count in your CDC pdf (1,769,940). Thus, more people would die from COVID-19 this year than all regular deaths combined. And this is with that 5X case count adjustment.

No offense, but you sound like a libertarian who never actually took the time to study economics in order to truly understand the nature of externalities. You are just mad are people infringing what you perceive to be your rights yet you are unwilling to acknowledge that you are infringing their rights through these negative externalities.

It would be worth reading Ronald Coase's "The Problem of Social Cost"[1] to perhaps refresh your knowledge of externalities. In it, he describes a situation (first described by Pigou) wherein a train catches a field on fire with sparks. He analyzes how if you force the train to not do this and side with the farmer, you are harming the train. While if you allow the train to do this, then you are harming the farmer. That is the nature of a negative externality -- inherently one person's perceived liberty/rights are infringed by another in either direction. But then if both rights are in conflict with one another, then surely they cannot both truly be rights for each cannot be maintained without the violation of the other. Thus, it is the role of the government to settle this by defining who has what rights.

[1] https://www.law.uchicago.edu/files/file/coase-problem.pdf