But  your beloved "noble savages" were still using blood sacrifices when the Spanish arrived.

The Spaniards had gone to the ritual cannibalism of the "Blood and Body of Christ" in their religious observances. 

twy4Dolphiin's point is that your "noble savages' were still a couple thousand years behind.   

The agriculture you are so proud of was actually and literally watered with the blood of their religious victims. 

The conquistadores were merely bloody warriors, whose violence was on a par with Apaches and similar warlike 'noble savages'.  

Look up the atrocities in the French and Indian Wars.  Both sides were eager participants.