It was an awful and criminal action to expel Jewish people from the Arab states and kingdoms bc of the actions of Zionists.
It's part of the long, complicated, sordid history of Zionism. I get the impression that Zionists don't bring it up much because it also leads to an investigation of the horrible treatment of Middle Eastern and North African Jews by the Ashkenazi Zionist power structure.
All that said; It's completely irrelevant to Zionism and the genocidal occupation of Palestine. The actions of foreign states do not bear on the action of the Zionist state and it's violence against Palestinians. "They did it first!" is not a justification for genocide, and saying "We did a genocide because they did it first" speaks to the depravity of the person making the argument.