Not to dismiss your rebuttal (I don’t believe the technology for voyages cross the south Pacific existed in the Americas [south of Greenland] prior to European contact either), but it is also possible that some unlucky fishermen got caught in a storm off the coast, and was unable to return to land. They miraculously managed to survive while being carried with the currents to e.g. Rapa Nui where they were saved by the local population, nurtured back to health, and lived there, had children and then died.