Israel was primarily taken by Ashkenazi Jews, whose DNA is heavily European. They spoke Yiddish, a Germanic language. If that gives them a right to Palestine, Europeans have a right to Africa.

The Jews who stayed were not Ashkenazi. They were called Sephardim then, but they're now called Mizrahi to distinguish them from the Sephardim who stayed in Europe after Spain expelled them. The Jewish Palestinians who stayed in Palestine certainly have a right to their land. As do the Muslim Palestinians who fled after Deir Yassin and were not permitted to return.

If I'm honest with you, you're assuming what you have heard is what's true.