"In some circumstances, perhaps many, young and middle-age individuals may want to risk the possibility of getting infected as opposed to missing some important (or unimportant) event. It is about rankings and value scales."
No, it isn't the risk of an individual getting sick that matters, it is the external cost on society and others that it causes. Someone who decides, for example, to go to a business meeting when they should be at home isolating themselves may, like the person here in New Hampshire, infect other people. Those people then bear the cost, potentially their lives, of the choice of the person who didn't want to miss an "unimportant" event.
If the person who spread the illness had to pay for the cost of the resulting infections, or bore criminal responsibility, I think the "rankings and value scales" would be quite different.
There are lots of things people don't do not because of the cost to them, but because of the potential cost to others.
Excellent comment.