On a demonstration near the Israeli embassy during the Hezbollah-Israeli war in Lebanon, I talked with a well-known anti-Israel activist, a woman in her mid-50s, whom I've know since she was 16.
Discussing the agitation for a boycott of Israel, I conceded that on principle a case might be made for some sort of boycott.
Except, I said, that "any boycott movement against Israel would soon turn into a Jew-hunt".
She responded candidly: "So what?"
So what? A boycott would be an ineffectual, crude, and indiscriminate weapon. And its political cost would be a campaign against Jews - "Zionists" - who refused to support it. That would mean, as big an upsurge of anti-Jewish, anti-Semitic, agitation as the organisers of a boycott could whip up.
Against a background of a steep rise in attacks on Jews in the street, and attacks on synagogues and Jewish graveyards, a boycott would do immensely more harm across the world than it could possibly do good in Israel/Palestine.
The woman I was speaking to is of distant Jewish background. A once-upon-a-time revolutionary socialist, she now describes herself as a "one-campaign person".
But that is the trouble with the "one-issue" - and sometimes monomaniacal - approach of the high-volume anti-Israel agitators. It blinkers them. It makes people who aren't necessarily stupid, politically very stupid.
Often it is a matter of "excess of love" and indignation on behalf of the Palestinians confusing and bewildering them. But for many of the obsessive anti-Israel campaigners the expression of maximum hostility to Israel, rather than concern for the Palestinians, is unmistakably the driving force.
They actively oppose the proposal for a sovereign independent Palestinian state alongside Israel - the only plausible plan to rescue the Palestinians from the unequal conflict with Israel.
The SWP paper Socialist Worker responded to the killing by the Israeli army of nine Islamist militants on the Mavi Marmara with the page one headline call to the world in general to "Rise Up Against Israel".
There is nothing at all to be said that can justify the Israeli killings on the ship. Least of all did they make sense in terms of defending Israel.
But the notion that the killings should be met by a world "rising up against Israel" says more about the state of mind of the SWP, as veteran of a decade of alliance with Islamic clerical fascism, than about anything else.
In effect, SW responds to the killing by the Israeli army of nine Muslim militants with the reiteration of its demand for the destruction of Israel and the forcible removal of self-determination for the Israeli Jewish nation.
To put it at its weakest, that is political hysteria. It is in practice, implicitly, and whatever the personal intentions of SWPers, anti-Jewish hysteria. If enough people paid attention to the SWP and acted on its call, it could not but lead to an anti-semitic movement.
It is possible for the SWP to do this - and no doubt the leaders of the SWP think it is laudable - because of its basic politics on the Israel-Palestine conflict.
It rejects the political solution favoured since 1988 by the Palestine Liberation Organisation, an independent Palestinian state alongside Israel. In internal Palestinian politics, it allies with the clerical-fascist Hamas.
To be sure, the PLO proposal for a "two states" solution includes the demand for the "right of return" of the five million descendants of Palestinians who lived in what is now Israel 60 years ago. Unless that could be reduced in negotiations to some token population movements plus financial compensation, it is just another demand, slightly hidden, for the destruction of Israel.
But in real negotiations about an independent Palestinian state in contiguous territory it might well be reduced to something that the Israeli Jewish nation could live with without abandoning self-determination.
There is good reason to be angry with Israel and for condemning the assault on the ship - and much else.
Too often the anger is used as an excuse for advocating the root-and-branch destruction of Israel, and so - since Israel would not voluntarily agree to be destroyed - endorsing any sort of war on Israel which Arab chauvinists and Islamists feel able to mount.
The renewed call for boycotting Israel and making it a "pariah state" is an expression of that drive. The response of the woman on the demonstration - so what if there is a Jew-hunt? - is part of that mindset.
Serious people will reject the Arab or Islamic chauvinist programme of destroying Israel. We will go on advocating the the only solution that can realistically help the Palestinians - two states, an independent Palestinian state alongside Israel.
To the point here, that also means the continued existence of Israel alongside a Palestinian state.
We will condemn what needs to be condemned, and in the first political place condemn Israel's refusal to use its present strength to achieve the equitable solution of a Palestinian state. Political hysteria and "so what?" self-righteousness will not help the Palestinians.