There have been many times when anti-Semitism has taken the form of sneering at Jews and Arabs at the same time, the basic theme being that European Jews were just a sort of Arabs, and both types of Semites were equally alien and suspect.

That would have been more so in the early years of the century, before the Balfour Declaration.

If Arabs were not targeted in Europe, it seems pretty clear that the essential reason was because, up until a few years ago, there weren't very many Arabs in Europe to target.

And I would suspect that in France today, for example, where you find someone who prejudiced against Jews, they are also going to be prejudiced against Arabs.

I'd see the use of the term in this context perfectly justifiable. It also has the effect of encouraging people to recognise the common features in prejudice against and persecution of the two "Semitic peoples".