American Jewish liberals who use it do so in bad faith, and what they mean by the term is not what Americans hear
Even though the term “Israel-Firster,” taken literally, is a fair, accurate description of any number of American Jews – those whose main concern in American politics is its effect on Israel – it shouldn’t be used. There are a couple of reasons why.
For one, when American liberals, almost always Jews themselves, use it to slam American Jewish Likud types, they’re using the term in bad faith. They’re not honestly bothered by Americans whose chief political interest is the welfare of another country; neither Ireland-Firsters, nor Mexico-Firsters, nor Southern-Sudan-Firsters, nor Palestine-Firsters upset them, and neither do Israel-Firsters. They’re put off, instead, by the intimidating rhetoric of so many of these American Likud types; I’m convinced that M.J. Rosenberg, Joe Klein, Glenn Greenwald and others who use the term “Israel-Firster” do so as a way of getting back at all those right-wingers who call them self-hating Jews. This is understandable, but not right. They should slam the American Jewish hawks on Israel for slammable offenses, of which there is, of course, no shortage.
The other reason not to use “Israel-Firster” is that unless you just can’t avoid it, such as with the term “Israel lobby,” you should not use terms that have anti-Semitic connotations, even when their literal meaning is fair and accurate. In America, “Israel-Firster” is not heard literally to mean an American Jew whose first political concern is Israel – it’s heard to mean “American Jewish traitor,” which in America is just as bad and much more dangerous a slur than “self-hating Jew.” I don’t believe for a second that Rosenberg, Klein, Greenwald et al mean their words to have that effect, but that is the effect.
There are any number of other strong pejoratives for the Adelsons, Morton Kleins and other American Jewish Likud types that can be used in good faith, and that do not have anti-Semitic connotations. For instance, “Arab-bashers” is one I’ve turned to lately.