It is often said the Crusades, which killed millions of Muslims, were a noble undertaking by the Vatican because without them we would now be Muslims. We don’t know this and I have my doubts.
When Europeans came to the Americas there were civilizations here that were, to say the least, noteworthy. The Incas and Aztecs, among others, were advanced in mathematics and astronomy. Their organizational skills were exceptionally well developed. They bred animals and crops. They did not have the weapons Europeans had but might have been more successful against the European invasion but for one misfortune, disease.