I'm very interested in how you know that these people were savages, since no living person has ever had any contact with these peoples. They died out from diseases indavertantly brought to the New World by explorers. They died of these diseases spreading through the indigenous populations without these remote peoples ever knowing where the diseases came from or how to deal with them.
What we do know is that they maintained populations of millions in areas that are now near wilderness. There isn't any reason to think that they were savages, as they were settled agricultural peoples who built massive earthen causeways and raised hillocks for settlement - often nearly a mile across. They lived in villages and towns with populations numbering well into the thousands. They terraformed the Amazon basin, leaving their man-made fertile soils for us to marvel over. They are the exact opposite of the "noble savage" leftists like to fantacize over.
Among all the evidence available to us, I'm not aware of a single element that would lead me to call these ancient peoples savages.
Now there's a historically significant trick: kill millions of gentle savages from diseases inadvertently introduced by those nasty European white guys but not as living persons who ever had contact with them. They must have used either dead guys or the post office... but I repeat myself...
The best indicator that whatever number existed were savages is the simple knowledge that they are almost entirely gone.