But Jews seem to have a tradition of just the opposite in just about everything else, with American politics being the anomaly.
There are old jokes from the Jewish comedians along the lines of "Put (pick a number) of Jews in a room and you'll get (more than that number) opinions." And I've heard (what I presume to be true) family stories about a half dozen Jewish families living in a small New Jersey town in the 1920s and none of them getting along with one another.
Even in political matters, there are jokes that the multiplicity of political parties in Israel reflects the many conflicting opinions and vigorous debates that occur among relatively small numbers of Jews. Also, British Jews seem to be more divided in their allegiance to political parties.
So why are American Jews today - if we take the Pew results at face value - so far to the left? A lot of it is brainwashing and mythology passed down through the generations, starting with immigrants from pre-Soviet Eastern Europe from whom the majority of today's American Jews are descended. Leftist ideologies were popular in Eastern Europe in the late nineteenth century up until WWI, the period of by far the greatest Jewish immigration to the US. And that cohort of Eastern European Jewish immigrants had never experienced the ill effects of Communism up close and personal, as much later Eastern European immigrants did.
The answer to this is context. In some contexts, Jews are wildly open minded. In others, Political Correct thinking forms an implacable group norm. I belong to a "Liberal" congregation and my presence is like a huge wet blanket because I will "reproach" when people make statements that I believe are unfair even at the cost of my own acceptance. I am just tolerated because of this and not eligible for any leadership position or position of authority. It is a price if you see it as that. But, we see this same system in the Universities of America.. Conservative voices are tolerated at best and completely excluded if they cause "too much" pain.
This is not necessarily what you could call brain washing but the techniques are definitely those of the commissars and these people are concentrated primarily in the secular and leftist (Reform, Humanist and elements of the Modern Orthodox communities) but the "theoretical" work to understand how the tactics of just a few well placed "minders" or operatives can move a whole community even against their own interests have just been recently exposed as part of the growing body of knowledge called "Crowd Sourcing."
Though I don't expect many folks to get this, the best summary the power of "Political Correct" speech codes and the creation of "group norms" that are enforced by group members is available here:
Dunbar, Altruistic Punishment, and Meta-Moderation
Every Tea Party Member, Every Pro-Lifer and any real "Human Rights activist" needs to understand this process, and especially the leaders need to get their heads around this data.
This is how the Black community, Jewish Community, and many others are continuously played into rejecting all messages of the reality of their situation vs. the fantasy that their "appointed" leaders are spinning. Margaret Sanger and bunch understood with without the graphs and such. They knew if you got Black Ministers and Rabbis to accept abortion as a "positive" good then their congregations would happily create their own "gas chambers" and kill their very own children so that in just a few generations, these unwanted people would be wiped from the face of this earth.