It’s also not unrealistic to imagine that there were a few places around that were near ideal for long term habitation, if not settlement. It can reasonably be assumed that much migration happens only when resources run out in an area.
So if a group found a sheltered valley, with lots of game animals and fresh water fish, easy to catch by hand in shallows, in a temperate area, they might occupy the place for several years until the bounty ran out.
The difference between that and a settlement would be the remains, or lack thereof, of them trying to create sustainability in the place. Some way of replenishing what they needed to remain.
This guy uses the word “harvest” a touch loosely, I’m guessing. Does he have any evidence that these “settlements” engaged in actually control of the food supply (and storage for later use), or, as Popocatapetl notes, merely taking advantage of natural abundance where it was found?
There’s the difference: using what’s found as against making it.