I don't think it's bizarre; I think there's been a step function in overt antisemitism in Europe, which is what he's seizing on. That he's an awful and ineffective messenger for that concern shouldn't blind us to the legitimacy of the underlying claim.

there has been antisemitism historically all over Christendom and Islamdom (in a similar way to the Jews of Jewdom declaring themselves God's chosen people). Viewed in that context, it's an error to describe American antisemitism as deep, it was always shallower than all the rest. As a result, America has a proportionately very high Jewish population, and with the 20th century decline of "class based" discrimination (generally in the form of WASP-control of social institutions) Jews in the US have flourished and appear at very high rates throughout the knowledge economy meritocracy.