Put aside many other incorrect informations written on the article, I just want to say that a couple of years ago I visited National Science Museum in Tokyo and there are two entire floors dedicated to talk about Japanese's root. One of it said that the true native Japanese came from the mainland 50,000 years ago when they first invented large ships.
Secondly, there are artifacts and ancient pots remains that can be dated 70,000 years ago and trees and something which I cannot remember well.
After years of living here, I can only say don't believe anything on the article. Especially the fact that it didn't mention Ryukyuans.