I always thought the idea that humans did not arrive in the Americas until after the last ice age was laughable. Less than 15,000 years and they settled the Americas from Alaska/Northern Canada to the tip of South America? No way.
Why not?
Lots of food, and almost no disease. Nothing to do but hunt lots of stupid big game and make babies.
Starting with just 20 people, you populate both continents in a thousand years.
A bigger problem is the oldest stuff is in South America, like at Monte Verde.
Some years ago I was talking with a woman in an east Coast bar. She was an anthropologist from California. This was during the time when no one before Clovis was still the general view. She said she was connected with a small group that had found remains they believed were around 200,000 years old and were in trouble for their belief. I wonder if this very old remains info has ever made it into the more general ancient human remains controversy/discussion?