"are they that controlled by their culture?"
Aren't most people?
People are most likely their parents' religion and parents' politics.
Why should Jews be any diffent than any body else?
This principle applies to other groups and in other venues. For instance, Irish and Poles, whose Catholicism was persecuted by Protestants in the former instance and Communists in the latter, tend to be more loyal to their ancestral faith and more resistant to the secularism that has overtaken other European countries. The Irish Catholic may see or hear a Baptist missionary and be reminded of Oliver Cromwell and the Penal Laws, even though the Baptists had nothing to do with his ancestors' misfortunes and were themselves victimized by the same Anglicans and Puritans who reduced the Irish Catholics to destitution.
Past persecution of one's ancestors is an incredibly strong form of inoculation. Even though liberalism is against the best interests of both Jews and blacks, only a severe setback to their present interests at the hands of the Left will persuade them to abandon their own leftist politics.