The Spanish treated Amerindians in South America decidedly better than the "Anglos" did in North America. Which is why many more survived in Spanish territories.
The Spanish regarded the Amerindians as sources of labor on farms and mines, as well as souls to be converted. Thus, the Spanish at least treated them just well enough to ensure that a large number survived. Attempts were also made to convert them to Catholicism, and once this was done, in integrate them into "society," even if it was at the bottom.
In North America on the other hand, the Anglo-Saxons basically "ran the Amerindians out of town." The survivors of the resulting confrontations were rounded up and placed on reservations in places like the Badlands of South Dakota, basically the worst land on the continent. And I use the word "survivor" as a reference to what happened to the "others." Apart from the occasional odd exception, there was no "mixing" between whites and Amerindians in North America. Certainly no attempt to integrate most Indians into "American" society.
The Spanish drove the Jews and Moors out of Spain because they were members of "established" religions that were not "convertible. But they adopted a softer policy toward the Amerindians in South America because they were seen as "convertible." In the end, that was quite a bit better than the Anglo-Saxons in North America treated their Amerindians.