Excellent discussion and Stef nailed it. FWIW there are no grey areas. Someone who suspects they have a transmissible disease and continues to mix with others is acting irrationally by effectively initiating force against others-this is the area in which a Government can and should act. No one has a right to demand, or to expect others sacrifice their lives and happiness for them. If some people want to cower in their homes, they have the right to do so, but they cannot demand that the healthy give up their lives and stay sealed up to protect them.
What we have here is altruism's ugly mug masquerading as something noble. It's why every discussion seems to include an attempt to shame those wanting to be free by accusing them of wanting to kill old people. There is an equivocation on the concept of saving "lives". This treats human life as homogenous like a field of wheat stalks, where as "life" for man requires more than simply existing vs not existing. Each life has a value, but unless man has the freedom to act rationally, to think, to produce, then that life is diminished to the point of being valueless. Those who demand others give up their freedom to act are initiating force against peaceful people and I expect to see a sharp rise in suicide, alcoholism, drug use, depression and crime as a result.