Here's one theory.

Apparently Tiernan is a known comedic critic of Catholicism.
Tiernan's audience appeared to be Irish.
There has been a long history of Catholic "Jew-killer" anti-Semitism, including complicity in the Holocaust during WWII.
*Perhaps* he was satirising Catholic anti-Semitism, before an Irish audience who would recognise it?

I'm not convinced, but offer it up as a suggestion.