Given how little we knew about the virus then going for herd immunity made no sense at all. For starters, we still don't know how long a person is immune to it once they get it. If it's only a matter of months, herd immunity can never work unless everyone in the country got it within a few months of each other. The death rate for that would be staggering, on the order of 5%, since hospitals would be overwhelmed. So basically, if Sweden was happy to kill off 5% of its population maybe it might get herd immunity, at least until the immune response wanes and people from outside the country bring it in. Then you start all over again. A doctor on the news discussed the herd immunity strategy espoused by Dr. Atlas, head of Trump's coronavirus task force. Basically, he said it's mass murder. Maybe you would have 6 to 10 million deaths in the US in the first year, then 1 million deaths annually forever, or at least until the virus mutated into a less lethal strain and that strain took over, which of course might not happen.