The problem with the identity politics of this, or any other sort is what my former professor at Rutgers, Eviatar Zerubavel calls "cognitive lumping and splitting." The constructors of such identities selectively focus on and emphasize certain traits (cognitive lumping) while ignore other traits (cognitive splitting). The same pertains to their view of history or rather historical mythology - certain events are brought to the lime light while other are conveniently forgotten.
A "true" ethnic identity - Jewish, Black, Polish, Irish, Latino, etc. is constructed by emphasizing stereotypical traits associated with these ethnic groups as a "master status" that defines a person - while ignoring all other traits. To say one is a "Jew" (or any other ethnic identity label) in the US is tantamount to bringing his/her religion/ethnicity as the defining feature while ignoring all other influences of the US society on that person - class, education, wealth, etc..
Of course this works both ways - to create both a club mentality and ostracism. Thus, those who criticize neocons as 'Jews' again concentrate on one arbitrary trait of that person's social status (ethnicity/religion) while ignoring all other (class, upbringing, education, social networks, political affiliations, etc.). This way of thinking is not much different from associating dark skin color with criminality, political ideology ("communism" or "capitalism") with social or economic problems experienced by certain countries, or for that matter Islamic faith with terrorism.
Wojtek