More to the story than just those at Nagasaki.
“The surprising survival of the Jesuits in Hiroshima is similar to that reported in Nagasaki, where a Franciscan friary built by St. Maximilian Kolbe also went unaffected.”
Oddly enough, one possible reason has been advanced by Indian traditional healers in South America. Formerly called “witch” healers, most are now Catholic, and reject the term “witch”, preferring “traditional” healers, as they use traditional methods to heal, but without the paganism.
In any event, they are very impressed by Catholic clergy because of their chastity, which they believe can be channeled through self discipline into great spiritual strength. By their traditions, at least some Catholic clergy should have super-human abilities because they preserve the strength used for sex and making children.
“This is how they can convey the prayers of others to heaven”, for example. “That is why Catholic clergy are so hard to wipe out”, in the reign of tyrants.
It is said that, when the Roman legions destroyed Jerusalem in 70 AD, the entire city, with the exception of the Upper Room where the Last Supper took place, was torn down.
Also, no Christians were left in the city when it was destroyed — they had all fled to other parts of Judea just as Christ told them to, forty years earlier.