This is flat-out untrue.
If you are my age, you will remember the American Jewish Committee from the 1950's and 60's.
The American Jewish Committee was the national organization of Reform Jews organized primarily to deal with the emergence of Israel.
The AJC had a very straight forward Israel position. Israel had nothing to do with American Jews. It was just as a new country independent of Jews in America. The AJC emphasized that Jews were a member of a religion.
The object of the AJC, since I knew the president and several high-ranking officers personally, was to expedite assimilation of American Jews in America. Being 'just a religion' made that possible.
With that as my history, it is clear to me that the modern Reform Jews and left wing Jews are direct heirs of the AJC position. Their off-putting relationship to Israel is strictly to benefit their own desired assimilation in America.