Respectfully would have eliminated a massive amount of atrocities, but the end result would have been similar: most of the native popularion dead in the first 150 years of contact. The Americas went from 50-100 million people to fewer than 5 million natives because of disease.
As atrocious as it was, it was pretty late. The largest pandemics were probably hundreds of years prior. Some believe the herds of buffalo etc was a sign of an ecosystem in great change, where the change was extinction of societies that previously tended the land.
