This WSJ article from '09 sheds light on the matter:
[C]ontrary to stereotype, [anti-Semitism does] not have particularly ancient roots in Egypt. Until Egypt's Jews were expelled by Gamal Abdel Nasser in the 1950s and '60s, Egypt had a millennia-old, thriving Jewish community. As late as the 1930s, Jewish politicians occupied ministerial posts in Egyptian governments and participated in nationalist politics.
But all that changed with the rise of totalitarian and fascist movements in Europe, which found more than their share of imitators in the Arab world. When Egypt's monarchy was overthrown in 1952 by a military coup, anti-Semitism became an ideological pillar of the new totalitarian dispensation.You mean revelers in Tahrir Square are not just like you and moi--freedom lovers looking for peace and quiet and democracy--but are out-and-out Jew-haters--Naziesque? Would someone puh-leeze let Anderson Cooper and the other MSMers in on that nasty little secret, so they can knock it off with all the sentimental gush?
Since then, Egypt has evolved, coming to terms (of a sort) with Israel and adopting some market-based economic principles. But anti-Semitism remains the glue holding Egypt's disparate political forces together. This is especially true of the so-called liberals, who think they can traffic on their anti-Semitism to gain favor in quarters where they would otherwise be suspect.
Westerners, who tend to treat Arabs with a condescension masked as "understanding," may be quick to dismiss all this as a function of anger at Israeli policies and therefore irrelevant to the development of liberal politics in the Arab world. Yet a liberal movement that winds up espousing the kind of anti-Semitism that would have done the Nazis proud is, quite simply, not liberal...