I agree. As for why American Jews favor the left, I agree you have to go back in time. In addition to the reasons you site, I would add that Jewish progressives and communists came to the aid of blacks who were suffering under racist policies in America. That progressivism eventually found its home in the Democratic party. The Democrats from the Jim Crow days, like Strom Thurmond, mostly ended up as conservative republicans. So the cultural lines were drawn. Or so it seems to me.
You are correct. Personally, I found the Jews I met so compelling in their political leanings, so willing to be on the front lines during the Civil Rights era, so engaged in family and intellectual life, that I converted from Catholicism to Judaism. Never looked back.
I grew up during the Civil Rights era, back when Boston Catholics were screaming against integration and southern Baptists were screaming epithets at little black girls trying to go to school.
I knew Jews who marched with King and did other things to help break down barriers. It is unfortunate that many today seem to ignore Israel and their own interests here in the States.