This argument might make some awful sense if THERE WERENT STILL NATIVE PEOPLES AND NATIONS BEING GENOCIDED!!!!!! Like I heard that COVID has wiped out like all the elders in some tribes because they had zero access to Healthcare, this IS genocide when you take structural impoverishment into account.
Horrible. Among all the other things wrong with this, loss of culture and language is not a completely irreversible process. Indigenous people are fighting like hell to preserve their languages and cultural knowledge, and while the loss of elders (especially with COVID) is tragic, it's totally false to say "their ancestors wouldn't recognise them." Look at this chad's language progress in a couple of years: https://www.youtube.com/watch?v=Mrqn_EQd5QY
Beyond what everyone else said. It also bears mentioning that many native american tribes weren't fully subjugated until the mid to late 1800s. Even later when we consider places like Alaska and Hawaii.