I think you were a bit lax on the kon-tiki hypothesis. It didn't just posit the west-to-east colonization of Polynesia from South America, but that this was done be white-people originating in the middle east.
So while there is genetic evidence for contact between South America and Polynesia, that evidence is also evidence against the Kon-Tiki hypothesis.
So while there is genetic evidence for contact between South America and Polynesia, that evidence is also evidence against the Kon-Tiki hypothesis.