Are they armed with a vaccine ? Otherwise how would being armed help?
They may not be able to compel anyone to treat them, but they can take a few doctors with them out of spite to make sure the rest of us are as screwed as they are.
Also this virus is a bell curve not a cutoff threshold. It has killed many young people. If you let it run wild , it can even come for you.
The common flu has been us for decades. What if COVID-19 became like the flu. A seasonal thing that evolves a bit every year. Soon there is a time bomb strain that kills 10% of the population but only kicks in after a month.
Something like that could wipe off a billion people from the planet. The only planet we know that can sustain intelligent life.
There are a few of these arguments in this thread, even.
Fortunately there isn't much serious discussion of this approach outside of certain think tanks because the optics are bad even for true died in the wool libertarians.
You'll even see arguments like "more people will die of the quarantine because they have no job if we keep the economy stopped for much longer".
IMHO this kind of one sided thinking comes from only considering the markets when making a decision. The markets don't care if you live or die, only that money is being made and spent.