It may well be that New York City is a center of Liberalism in the USA and that is where a lot of the USA’s jews are. Remember what Jesse Jackson called NYC.
Jews have always been leftists in America, it isn't something from the last 50 years or so, or because of NYC.
In the 1920 election the (actual) Socialist party got 38% of the Jewish vote, the republicans have never won it, FDR was winning 90% of the Jewish vote when Protestant America was voting against him.