I'd love to support you on this one YNF but you're not seeing the big picture. We all came from somewhere. Indigenous peoples have migrated just as much as any other culture or people. Many others have been mentioned in the comments below.
And you're missing one other point that I think is crucial; all the possibilities are still just theories. And no one who does this work has said otherwise. Would it really bother you if your ancestors from 15,000 years ago came onto this continent from someplace else? How does that undermine Indigenous occupation and claims to this land prior to White people arriving and taking it from them! You would still be the original first inhabitants, here for many thousands of years as claimed.
What all the new studies are attempting to do is to trace the movements and origins by looking at human and nonhuman genomic DNA. These studies are just beginning but are beginning to yield very interesting results. And I just read an article about this whole topic that appeared in the May 2021 edition of Scientific American. At the end of that article, the authors say, and I quote, "It is important that geneticists work with Indigenous communities to ensure that the quest for genetic knowledge does not perpetuate further harms"
They also say "The use of nonhuman DNA can potentially illuminate human population movements while respecting the sacredness of Indigenous remains."
So classifying all this research in such a negative light is a bit naive, IMHO. Yes, this kind of work done in the past was harmful and degrading and perpetuated racism and prejudice against Indigenous Peoples but times are changing and researchers are not behaving as they did in generations past. They are coming from a place of respect. At least that's what they say and that's my hope. The article also mentions how hard it is to get Indigenous Peoples to work with them because of how badly these people were treated in the past. Trust takes time to build after harm and trauma have been experienced and they know this. And they are willing to do it one little step at a time.
Two-eyed seeing. Working together to learn together to incorporate all the different ways of knowing. For me, that is the ultimate goal where everyone learns and benefits.
And that's all I'm gonna say for now.
Be well, YNF. Peace be with you.