The idea that all Jews are socialists is a stereotype. Depending on who you are and where your ideology falls on the bell curve of political thinking, Jews are either socialists because they are anti-American or they are socialists because Jews have a longstanding religious tradition of tikkun olam. Both of these theories exemplify the hyper-generalized thinking that derives from stereotypes which are, in and of themselves, hypergeneralized end-results that justify the means of their creators. All Jews are no more anti-American than all Jews are pro-saving the world. The only thing All Jews are, are individuals who happen to identify themselves as Jewish. The definitions from that point on, more often than not, belong to the end user rather than the creator themselves.
As to why All Jews tend to be stereotyped as socialists, well, that theory has never quite been examined in full. Probably because no one with a solid interest in the theory can drum up enough of an objective opinion when it comes to the hot-button phraseology. To be interested in socialism to begin with, one is either definitively pro or definitively anti-socialist. That perspective alone is enough to kill polite conversation, let alone anything bordering on serious repartee.
But, what if you weren't necessarily biased? What if you had no relative tie to the swath of Jewish immigrants pouring into the Lower East Side from Eastern Europe in the late 1800s? After all, that's where the theory began, right, that All Jews are socialists? So many of them were reds that they established a daily paper in their own language, the Forverts, to get their message to the masses. Of course, history will show that for as many Jews who were socialists, just as many weren't, but they're the boring part of this story. For the real historian (not the political muppet) the question is, what motivated socialism among Jews in the first place?
Well, if you lived in a ghetto and were forced to listen to a group of Rabbis tell you how to live and you grew up thinking you could never leave that ghetto because the hoards of gentiles who tended to raid that ghetto, destroy homes, rape women, and steal your livelihood would probably come after you and kill you, you'd probably be looking for an answer to your problems, too. What better answer than an ideology that preaches that the little man deserves to have as much money and power as the big maccas?
It really is that simple, and it really has as little to do with overthrowing America as it does with a religious notion about repairing the world. It boils down to seeking out a life-saving methodology. The irony is: Who knew socialism would be the ideology responsible for the murder of tens of millions of Jewish lives over the course of the 20th century?
At the time, it sounded better than the ghettos and the pogroms.
So, the most I could possibly say about the Jewish embrace of Socialism is: Hindsight is 20/20.