Seriously, what Israel is doing today is no different from what the Nazis did before and at the beginning of World War II, extreme nationalism, illegal expansion, annexation of foreign territory claiming it historically belongs to them, propaganda using the latest technology, terrorizing neighbors, military at the center of society.
Nazism isn’t banned anywhere. If it were, Zionism and any other nationalism would most certainly be banned.
To answer your question, because it serves capital.