When Jewish intellectuals confuse their right to criticize specific policies of current or past Israeli governments with questioning the legitimacy of having a Jewish State, that is when they cross the line of legitimate debate and cross over into anti-Semitism, and thereby serve the purposes of the enemies of the Jewish people.
This position strikes me as over the top, perhaps even dangerous to the ‘legitimate debate’ Rabbi Grossman wants to encourage. Anti-Semitism is too often used as a cudgel (and, in its overuse, becomes an increasingly ineffective one) to silence anyone whose ideas and positions we don’t like. Rabbi Grossman’s guideline seems like a loyalty test for what sorts of positions Jews may take–to say nothing of what might be legitimate criticism by non-Jews.
Criticizing Israel isn’t anti-Semitic in and of itself. Neither, for that matter, is questioning the legitimacy of Israel to exist as a Jewish state–although, personally, I strenuously disagree with this position and believe such views can justly be termed anti-Zionist or anti-Israeli. Anti-Semitism comes into play when people criticize Israel for sins that they cheerfully overlook or for which they offer apologetics when committed by other countries in analogous situations–when they use their criticisms of Israel as a shield for their hatred of Jews. Mahmoud Ahmadinejad is an anti-Semite, and a dangerous one at that. So are those who disparage Judaism or Jews’ ability to practice their religion freely. Let’s save the label for those who truly deserve it.