I think you missed the point. Covid is not fundamentally a different problem than other respiratory diseases in this setting. If we did not want elderly people to die due to respiratory distress, we would have always had measures to keep them totally apart from germs. Flu and other respiratory illnesses, long before covid, killed many many of the elderly.
So are you suggesting those people didn't matter? That they don't matter now? Why aren't you advocating to keep them safe?
Would you be willing to sit in a room, or an institution, with no one to talk to, not allowed out, staff all masked, for the remaining days of your life, in order to gain a few more months of life?
Most people would not, and forcing them to do so, even to protect others, is morally degraded.
That some residents may be younger is really neither here nor there. Many did not want that kind of isolation anyway, but even if they did, they still don't get to tell other people they also need to be isolated from the rest of society.