Reading Chabon’s afterword to ‘Gentlemen of the Road’, the comparison that came to mind was Rich Cohen’s non-fiction crime work, ‘Tough Jews’. Again we have a young American Jew whose self-image is bound up with the Woody Allen-style nebbish and feels the need for a more positive, macho stereotype, in this case Depression-era Jewish gangsters.
Cohen relates the negative self-image to the memory of the 6 million who, in his teenage eyes, went passively to the ovens-something, he feels, his Jewish mobsters would never have done. A later book (sorry, the title escapes me) tackles this head-on, being an account of Jewish resistance fighters in World War II.
Although Cohen does mention the Israelis, he obviously doesn’t feel a strong enough identification with them to claim Mossad etc as role models. Is it the same with Chabon? Perhaps American isolationism is to blame, as you say. Whatever the case, it will be interesting to see where Chabon’s journey of cultural self-exploration leads him next.

Actually, I think it might be fairer to call it a bias. Chabon’s far too smart to be unaware that in parts of the world without many Jews, Israel is the image of Jewishness that first comes to mind. But he’s writing as a Jew in (and, I think, writing that afterword for) a country with a fair number of Jews, where a certain construction of Jewishness is solidly embedded in both pop and high culture.

You might find this post of Abigail Nussbaum’s on, among other things, reading Yiddish Policemen’s Union as an Israeli interesting, if you haven’t run across it already.