There was a full fledged assault on the Jewish community near the Vatican. Read the book Growing up Jewish in Fascist Italy. The writer is not fond of Pius XII.
If somebody was a child at the time, their reminiscences would be frightening, and they would not be well disposed towards anyone perceived to be in authority. But their personal experience would not necessarily include any knowledge of diplomatic activity -- especially if the author was a young person at the time. Given the need for secrecy, that's not surprising.
Your initial statement, however, has been demonstrated to be false. Unless you can show something historical and documented (as opposed to the memoir of a young person), I don't see how you can assign blame so confidently.