You have to quote some official Catholic source from Luther's day in order to make this assertion worthy. Otherwise, it's just an opinion with no substance. Catholic doctrine was, and always has been, that unrepentent sin leads to eternal death.
"The fact is, Calvin's Geneva was a haven for Jews fleeing Catholic Europe. It should make you wonder how that rigid man's city could become a haven for unbelievers."
The fact is, that Spain was the largest haven for Jews for decades. But when the Jews who refused to convert were expelled by the King of Spain because he feared sedition and infiltration after 600 years of religious oppression by Muslims, the Pope in Rome was awaiting the expelled Jews with open arms and loving heart. The Jews arrived in Rome in the tens of thousands. Meanwhile, Luther was writing his deadly volumes about his hatred for Jews.