@Leyonhjelm Everyone has a bit of everything, it's been a somewhat global world for over two millennia.
But when people claim that an ethnicity is basically made up and has no historical continuity, the people making the claim have a lot to prove when it's an unusually coherent community that has been kept together by themselves and by outside persecuters, and when there's physical evidence like the "Cohen" gene.
The only two motivations I can see behind a claim like that are antisemitism and motivated ignorance, which is just antisemitism with extra steps.