In the story of Shaul slaughtering all of Novs residents in Tanakh, David takes the blame because he put the Kohanim in danger regardless of the fact that this had nothing to do with Shaul actually being the one to kill these people. Does this not apply to the Zionists who also put hundreds of thousands of Jewish lives in danger in the Arab world, even if they were not the ones to eventually kill them?

Your question is whether indirectly causing death is allowed, and the answer is definitely not. We believe that even one who caused death accidentally should examine his actions and must go to the city of refuge. All this is to stress the importance of saving life. Similarly, the Zionist act of declaring independence and fighting to protect Jewish security, are acts meant to save (!) many lives, and in fact have saved millions of lives of Jews who have been in danger, in Israel, the Sepharadic countries, Ethiopia, the Soviet Union etc. There is no logic whatsoever to connect that with the Arabs who never treated Jews well, and used their attacking Israel in the War of Independence as an excuse to mistreat us and force us to flee from their lands and seize our possessions. True, for 2,000 years, the Jews "fought with their passports" and not with weapons, but that is not the real and original Jewish way, as we clearly see throughout the Bible and learn from our Biblical heroes (Joshua, Gidon, Shimshon, Yiftach, King Shaul, King David, all the way down to the Maccabees), that having a Jewish State and army are the Jewish solution and clearly not the problem.