That's 100% the point. If you know who they are you can isolate them.
> Herd immunity hasn't worked. It's been a catastrophic failure that's flooded hospitals with very ill people.
I assume that you know many people with Polio then?
So even if young people do not die of Coronavirus (which we do not know for sure) they die because they cannot get medical treatment after cutting their finger on a rusty table edge, or get into a car accident and cannot get medical help, etc.
> I assume that you know many people with Polio then?
It's disingenuous at best to ignore that the parent comment referred specifically to seeking herd immunity (as opposed to early lockdown) of COVID-19.
What do you do with everyone else?