As to the population of Native Americans, perhaps you should read more carefully. The estimate of 900,000 was credible at the time -- 100 years ago. Since then, no attempt to discern the actual number has used such primitive methodology (they were estimates that were based on multiplying previously recorded estimates) and none have ever estimated the number to be so low. That's why I used the number 12 million, all of the most credibly studies hover around 12 million. It's funny that you "clarified" that 18 million is the highest estimate, since my post SAID that's the highest estimate. Either way, there's a more important number -- .8%. Native Americans used to comprise 100% of this country, now they are .8% of the nation's demographic. We took their land, brutally killed their men, women, and children, and subsequently destroyed major portions of their languages and cultural traditions, then we forced them to convert to Christianity.
I'm not sure why you would want to defend these actions. It removes any credibility you might otherwise retain.