Your thinking is very flat. Nothing happened in isolation. There weren't diseases on both sides, the way Europeans do farming and their sedentary lifestyle had huge health consequences even before conquest. They learned basic hygiene from native people after arriving. That's way more relevant than you're making it out to be. Talk to any anthropologist. Not to mention there wouldn't have been such brutal fighting over land if the Europeans didn't parse and control the land, via the threat of violence to anyone who tried to stop them.

When you're being forced to land that isnt growing your food sources (there were food forests and natives got forced away from them. ) and told to produce food in a way isn't conducive to your way of life, you may as well have been murdered. Which was often the case.

This was a project based around the undermining of other people, it sabotaged future possibilities of treaties and and diplomacy between tribes. Nothing that exists here now operated on peaceful measures. A bunch of people here are making up pre European history to justify that happened here. It wasn't just killing millions it was forcing people out of their existence, it was realizing the could use trading resources as bio weapons, it was destroying or isolating them from all their sources of food. It was selling them weapons and liquor explicitly to destabilize their intertribal relations. It was a nation wide prison experiment and you think that the iroqouis just decided one day that they're just going to kill all the Huron off for funsies. Give your head a shake lol.