I agree that Zionism is not “white supremacism”. That appears to me to be a projection of the defining characteristics of an altogether different context onto the quite different circumstances of the modern Middle East.
I also agree that Zionism is, broadly speaking and in theory, a rather typical nationalist movement with its origins in the growth of nationalism in Central and Eastern Europe during the latter half of the nineteenth century. In that sense, its self-image is akin to any number of rival national liberation movements of that time, manifesting in the context of the dissolution of the Russian, Austro-Hungarian, and Ottoman Empires.
However, that is only half the story, as the era of the rise of European nationalism was also the era of the assumption of global European supremacy and imperialism. This wouldn’t have mattered in the case of Zionism any more than it mattered in the case of, say, Serbian nationalism, if it wasn’t for one major unique characteristic of Zionism - that it was the national movement of a dispersed people with its geographical focus on a land where almost none of them lived, that was also inhabited by another people about to experience their own burgeoning nationalism.
So while beyond perhaps the extreme fringes Zionism never developed a grand ideology of explicit anti-Arab racial inferiority along the lines of, say, the racial attitudes of white America vis-a-vis African Americans, it brought to Palestine certain assumptions regarding the hierarchy of civilization and the ranking of non-European peoples such as the Arabs within that hierarchy. And so it tended to treat the Arabs with a degree of indifference or contempt, the Arabs being expected to basically prostrate themselves before the more advanced civilization in the ways that so many subjects of empire had in the century or so before around the world. And in the practical circumstances that the early Zionist settlers found themselves in, they adopted the familiar methods of settler-colonialism, and were unapologetic about recognizing it as such at the time. That is the Zionism experienced by the Palestinians on the ground, not as an abstract theory of Jewish liberation but as a manifestation of European imperialism directed at them.
So Zionism is quite unique being in origin both a nationalist liberation movement in the classic European form, and also a settler-colonial movement in the classic imperialist form, whatever other developments may have complicated this picture since (e.g. the migration of Mizrachi Jews since 1948). Due to the well known saga of Jewish history, it can be very hard for Jews to understand Zionism as anything other than the former; but in the face of their day-to-day experiences of Zionism, it’s almost impossible for Palestinians to understand it as anything other than the latter (a major exception who we should all be reading at these times would be Edward Said who, from an acknowledged position of relative privilege, made a huge effort to attempt to understand the genuine appeal of Zionism for Jews).