Political Zionism differed from other manifestations of European mainly in the fact that its sacred national soil lay outside Europe. Otherwise, it possessed all the characteristics of the other national movements of the day - a dedicated, visionary elite; a complex ideology based on nationalist interpretations of history and culture; a wide spectrum of political opinions; a mass clintele that still needed to be convinced; a full panoply of enemies; and, at the outset, no obvious chance of practical success.
Some of these Germans were Nazi-era colonists established in Eastern Europe after Nazis ethnically-cleansed the region of native Slavs. Many others, though, were essentially natives, living on territory long belonging to Germany or Prussia:
The forced migration of Germans dwarfs the mass-migration of Palestinians during the Arab-Israeli war of 1948. Casualties in European migrations were far greater than those in Palestine. Today, though, the various nationalisms of Poland, Russia, former Czechoslovakia and other countries are uncontroversial, while Zionism is highly controversial. I do not see outsiders complain about Polish or Czech imperialism, I do hear this about Israel
Perhaps a more useful discussion would explore Zionism in terms of ethnic nationalism instead of as a discrete movement. The idea that some kinds of ethnic nationalism are good while others are bad seems misleading.