People who claim to be anti-Zionist and not antisemitic offer some reasonable sounding arguments. The reason we know that these arguments are disingenuous is not that the arguments themselves are logically false, but that we have over a century of such arguments - and they morph over time, while keeping the common denominator of always targeting Jews.
They keep trying to refine their arguments but when you look at history, you can see that the arguments may change but the underlying antisemitism remains the same.
I just saw a neat example of this from a July 12, 1919 article in the Deseret Evening News ("Is 'Zionism' A Threat to World Peace?") where Palestinian Arabs are interviewed about why they are against Zionism.
Their anger is against the perception that the British conquered Palestine only to give it to the Jews, who did nothing to deserve it. They actually say that if Jews have the right to Palestine, then Indians have the right to New York - tacitly admitting Jewish indigeneity.
Then comes this:
You see? The problem is that the Jews didn't earn Palestine, fair and square, by winning it in a war. They were cheating (by, for example, buying farmland at inflated prices, which the article similarly describes as a nefarious Jewish plot.)
Is that argument no longer valid? Or was it simply a logical sounding excuse to justify antisemitism after the fact?
Just like today, the argument sounded like it has merit at the time. Only since 1948 and 1967, when Jews did defeat the Arabs in battle, do we see that it was simply an excuse for hate, dressing it up as something respectable using rhetoric. They keep moving the goalposts to find other reasons to hate the Jews that don't sound antisemitic - "refugees" or "occupation" or "settlements" or "apartheid." Then as now, these arguments are created to find respectable clothing to dress up pre-existing hate.
Just as the "anti-Zionist not antisemitic" arguments of the past changed to avoid looking foolish, so will today's. And the modern antisemites really, really don't want you to look at history.
