Ping.
There have been Jews and non-Jews living in "Palestine" for thousands of years; no doubt. I do not think this is where the justification for Zion lies. For me, it is the unique, singular genocidal assault on the Jews by the Nazis (unique in its scope, not occurence) for which they
deserved their own country purely--at least--for defensive purposes. Immediately after WWII, the world (other than the Arabs) agreed.
Also, remember this: the Torah relates how the invading Hebrews often killed the males and took the women for slaves and brides in the land of Canaan (Amalekites, Hittites, Edomites, etc.). The genes have mixed up a bit.