This is just demonstrably false (see, for one artistically valuable but hilariously naive example, the song "Cortez the Killer" by Neil Young), but will certainly be met by goalpost-moving of "nobody serious is saying that..."
I could have worded it better, but like I said original this particular silly talking point is hard to unpack and respond to since it’s such a non-sequitur.
https://en.wikipedia.org/wiki/Native_American_disease_and_ep...
The quote is from the section Disease as a weapon against Native Americans
The westerns saw the absolute devastation by their mere presences was causing unintentionally and occasionally decided to use it to their advantage purposefully...but I highly doubt that absent those occasions that we would have seen much different outcomes.
Absent total non-contact for the next two centuries...
2. As already mentioned in the other response to your comment there are multiple documented cases of deliberate infection, if that’s where you want to go.
95-99% of the time they just had to show up for it to happen
Nobody ever in any circumstances is stating or implying that native peoples did not engage in war, murder, etc before and during the arrival and colonization by Europeans. But that’s not the point. Native peoples died of natural causes while diseases Europeans introduced wiped them out en masse. The natural causes are not the point of the discussion.
The reality is there is a history of European empires colonizing and wiping out native peoples. If we refuse to look at this critically and learn from it then we have not improved beyond our ancestors. when this topic gets brought up, don’t bring up straw men based distractions. Engage in the discussion meaningfully with an open mind.