This is very true. While human migrations did occur, the notion that Indigenous Peoples crossed the land bridge in 15,000 BCE is an outdated piece of racist scholarship. I am disturbed that it's taking so long to effect the transition, but modern evidence and respect for Indigenous historical narratives are actually leading to a new understanding that shows that a migration happened much earlier - ca. 40,000 years ago. And of course, there's no attempt to charge it politically (i.e. "oh, but they came from somewhere else!)