before, during and after WWII we got the runners. That gene pool doesn't "fight", they survive and try to work within the system for their benefit and their family. The fighters were the ones that ended up in Poland, Israel and dead. The ones that "got along " or were smart enough to leave are here. So their fight or flight response is ......uh.... flight. They're the ones that figure if the SHTF they'll be looked upon as "the good American Jew" and not the hell raising liberty loving one.
I know several >10-12 Jewish families and know that only one has weapons of any kind. The one however has enough survival gear, ammo and weapons to arm a platoon. His mother was taken to the camps and he has no qualms about saying that before someone comes to "knock on the door", he'll fight. Because he said he didn't want to be seen on video running to an open pit while soldiers put a bullet in your back and bury you in a field while laughing like those old WWII videos of the Germans lining up the Jews who passively complied.
Rather, the majority is descended from Eastern European Jews (most of them from czarist Russia or Poland or Romania) who immigrated to the US earlier, from about 1880 to 1914. Most were poor when they arrived and their European experience made them susceptible to various socialist ideologies which were circulating in their areas of Europe at the time just prior to their immigration.