This is a frankly antisemitic argument. "Dual loyalties" is practically the kernel of all antisemitism.

what would you call Canadian citizens who hopped on the first plane to Israel to serve as reservists?

We cannot question their allegiance?

If an Iraqi did the same thing when the U.S invaded Iraq, you wouldn't question their loyalties?

Arab countries are within their right to question the allegiance of their population when their local population is conspiring (or suspected) against their national interests.

Do I need to remind you the Japanese internment camps in the United States?

It's 1956, it was before the mass surveillance era, internment and expelling was a valid solution when you stop a literal terrorist plot.

No, I don't think questioning the allegiance of pogrom victims is a good play.

No, there were no reports of a pogrom against Jews in Egypt in 1956. However, during the Suez Crisis in the same year, some Jewish individuals faced increased tensions and discrimination. Many Jews eventually left Egypt, but it wasn't a pogrom in the traditional sense.

In the context of a discussion about potential crimes against humanity, an argument that ethnic cleansing is sometimes ok feels particularly unconvincing.

This is again a frankly antisemitic argument. Arab Jewish people in Tunisia bore no responsibility whatsoever for what happened 1800 miles away from them. Racism isn't nuance, it's just racism.