Interesting piece, thanks for posting.
I was struck by this part “Many Pius XII supporters have maintained that had he spoken out about the Holocaust, he would have made the situation worse but Kertzer finds that hard to imagine.”
I too find it hard to imagine.
Pius believed in "shut the hell up and save lives". 688,000 Jews not murdered by the National Socialist German Workers' Party agree.
The Dutch bishops tried publicly opposing the roundup of Jews. The Nazis’ response was to accelerate their deportation program and to start killing converts from Judaism that they had previously spared.
https://www.ncregister.com/commentaries/the-bishops-who-defied-the-nazis
Pius XII was heavily involved in plots to kill Hitler, including the one that almost succeeded in July of 1944. He had already concluded that protesting merely invited reprisals, and that the only sensible course of action was to try to remove Hitler from the scene. Given that, and given that there were tens of thousands of Jews hidden in Catholic establishments just in Rome, calling attention to himself with vocal protests would have been extremely unwise.