I've been suspicious of that claim. If the Polynesians came from Asia and were able to reach the Americas, it's possible that there was latent communication between the two worlds but such communication happens at "generational" speeds.
We are certain at this point. The genetic testing is pretty conclusive.
Polynesians genetic testing
Humans arrived to rapa nui and other Pacific Islands relatively late, many thousands of years after the Holocene began. Stronger evidence of 13th century contact doesn't change anything about our understanding of the early history of the Americas.
That there were people and civilizations in the Americas before then is far from the point.
However, that's a wildly different topic than what the grandparent comment is talking about. I'm interpreting their comment in a charitable light because interpreting it more broadly quickly gets into hyperdiffusionism territory.
There is evidence of contact between Polynesian and South America. Like Polynesians having sweet potato. But not enough for visible changes of either one.
Civilization doesn't seem to spread by short contact, only close contact. Civilization is complex so a few ideas aren't enough to spread it. And it is hard for culture to accept that much change.
Isn't the latest research strongly implying they came by boat?