re: Why are American Jews liberal when that political philosophy is anti-Israel?

Jews are only liberal in their host nations throughout the diaspora. It's a comparative advantage strategy at behest of the host nation and culture, whilst allowing a cover for their ethno-religious apartheid nationalism and atrocities in their homeland.

American Jews becoming rightwingers in large quantities in the USA would create a hostile environment for them and put them on the extreme fringe due to their right wing foreign policy stance regarding Israel. It's a lot like National Socialism, really. German-Americans were always supporting left policies regarding civil rights and were always pro- labor union in their settlements throughout the Midwest, whilst simultaneously supporting the National Socialist cause and its policies for the Fatherland with their bunds.

Jews have to maintain the middleman status strategy in order to survive, and at the same time avoid acculturation, which in turn intentionally irritates the host nation and its peoples within the Jewish diaspora lands.

This likely explains why they are often viewed as difficult and untrustworthy, and therefore creating their own persecutions which enables them to maintain sort of a victim status to cover the atrocities of their homeland and those they have took part in throughout their history.