I'm not disagreeing that we need to let people be infected if we want to achieve herd immunity, but I think it's a tough choice in deciding which portion of the population you put out to partially die, since letting everyone out at once will result in some high R0 value again, and a vaccine may be on the way. These politicians are in a lose-lose situation here. Anything they do will result in someone being harmed.
[1] https://www.cdc.gov/coronavirus/2019-ncov/hcp/clinical-guida...
[2] https://www.mercurynews.com/2020/03/28/coronavirus-gov-newso...
It already happened in New York. Maybe not quite at exactly the the same scale, but it looked like it was pretty awful just the same.
NYC has had 12,774 deaths to date, out of 9 million people or so.
Lombardy has had 13,679 deaths with a total population of around 10 million.
So broadly, they're fairly similar, although Lombardy as a region is much larger than NYC.
Edit: I should add that I didn’t downvote.