Efforts to win support for right-wing Israeli policies are inevitably going to spin off accusations, like Mr Kirchik's, that Jews like Max Blumenthal who criticise Israel are self-hating or in some sense not real Jews. This is a familiar dynamic in ethnic nationalist politics; it's similar to what Slobodan Milosevic did to Serbian liberal opponents, what Putinists do to liberal Russian politicians, or what Mahmoud Ahmadinejad has done to his opponents in Iran. It's actually rather similar, for that matter, to what ethnic nationalists, actual anti-Semites, have always done to the Jews in their countriesclaiming they are not "real Russians", "real Englishmen", "real Frenchmen", "real Americans". If those who are slurring liberal Jews critical of right-wing Israeli policies were thoughtful people, this might give them pause. But, for the most part, they're not, and it won't.
If you don't agree with Jamie Kirchick, you're a self-hater if you're Jewish and an anti-Semite if you're not. I learned that a long time ago. If someone called Jamie a self-hating homo because he bravely takes on the gay left from time to time (and they do), he'd be right to be angry. Why can he not see the parallel?