No one should have been surprised that Helen Thomas, the antisemitic octogenarian of American journalism, said what was really on her mind when the rabbi David Nesenoff stuck a video camera in her face on the White House grounds late last month.

Her comments – that Jews should "get the hell out of Palestine" and "go home" to Poland and Germany – brought Thomas's 67-year career to an abrupt end. On Monday, she announced her retirement from the Hearst news service amid condemnation from the White House and her fellow reporters.

"It's hard to hear the words 'the Jews of Germany and Poland' and not think of anything but the millions and millions of Jews who were incarcerated, enslaved, tortured, starved and exterminated in the Holocaust," wrote Rachel Sklar at Mediaite, concluding: "Which means that, sad as I am, Helen Thomas can no longer be a hero to me."

Yet how different was it, really, from Thomas's statement of last week (it would be hard to call it a question) that the Israeli military's attack on the Gaza-bound flotilla was "a deliberate massacre"? The flotilla incident could be called many things – a tragic miscalculation, a hubristic blunder, a disaster that could and should bring down Israel's intransigent rightwing government.

But to assert, as Thomas did, that Israeli commandos landed on the deck of the Mavi Marmara with the express intent of shedding Muslim blood is to deny Israel's very legitimacy as a state. Which is why Michael Hirschorn wrote on Twitter: "Helen Thomas did us all a favour: she surfaced the subtext." (He appended his tweet with the hashtag "#usefulidiots".)

The rightwing media-watch site NewsBusters last week posted a classic 2006 video of Thomas badgering the late Tony Snow, spokesman for then-president George W Bush, about why the United States hadn't compelled Israel to cease its incursion into Lebanon.

Snow responds with a cheap shot, thanking Thomas for "the Hezbollah view", and then attempts to answer her question amid her repeated interruptions. It is enlightening only to the extent that it shows Thomas's anti-Israel beliefs had been well known for quite some time.

In fact, Boston University journalism professor Robert Zelnick told Politico that Thomas's "bias regarding Israel has long been known to anyone – including this commentator – who has spent five minutes in her company." Zelnick, a former ABC News reporter, is someone I know and trust.

There was a time when Thomas was considered a serious journalist – a trailblazing woman in a business dominated by men. I recall seeing her speak in the mid-1970s, when she was White House bureau chief for United Press International (then a serious competitor to the Associated Press) and I was a journalism student. But that was long ago.

Thomas, to her credit, quit UPI in 2000 after it was acquired by a company controlled by the reverend Sun Myung Moon. Until Monday, she had been employed as a columnist for Hearst, although hardly anyone ever saw her work. In 2003, Slate's Jack Shafer wrote, that the only Hearst papers that ran her column more than occasionally were the Houston Chronicle and the Seattle Post-Intelligencer. And the PI last year was downsized into a local website.

In recent years, Thomas's main role, as far as anyone could tell, was to take advantage of her position as the senior White House correspondent in order to engage in a kind of performance art. She knew no one was reading her, and hadn't for some time. But she could ask impertinent questions that really had no answer, delighting many liberals, especially during the era of George W Bush, who she memorably called "the worst president ever".

Shafer, in his Slate piece, documented a number of Thomasisms. In my favourite, she unintentionally reveals her bias against Israel in asking (well, speechifying at) George Bush Sr about Iraq's missile attack on Israel during the 1991 Gulf War:

Thomas: "Mr President, two days ago you launched a war, and war is inherently a two-way street. Why should you be surprised or outraged when there is an act of retaliation?"

Bush: "Against a country that's innocent and is not involved in it? That's what I'm saying."

Thomas: "Well …"

Well, indeed.

Those of us who consider ourselves to be pro-Israel liberals have plenty to be angry about these days, as Binyamin Netanyahu's government has handed the enemies of Israel a propaganda victory of incalculable value. The liberal Israeli newspaper Haaretz has been a refreshing counterpoint to the timidity of the American media. So have harshly critical pieces by supporters of Israel like Leon Wieseltier, writing in the New Republic, and Christopher Hitchens, in Slate. (Hitchens, you may recall, used to hold rather different views.)

But alongside such responsible critics are the Thomases of the world – "useful idiots" who, through their outbursts, reveal they aren't interested in peace or a two-state solution so much as they are indulging romantic notions about Palestine and Hamas.

It would be unkind to suggest that Thomas, who was born in Kentucky, should "go home" to Lebanon, from which her parents immigrated. But it would be in keeping with her own loathsome views.

In going off for the benefit of Nesenoff, she did us a service: she revealed to her fans the root of her harsh rhetoric on the Middle East. She is a garden-variety antisemite, and her departure was long overdue.

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