The Arabs who did not wish to move out of what was ordained Israeli territory were invited by the Jews to be Israelis. With full rights. They chose instead to kill the Jews. They were defeated. They have no rights in Israel. They forfeited them.
--------------------------------------------
Actually after the Jewish massacre at Dayr Yasin, the Jewish forces threatened other Arab Palestinians with the same if they did not abandon their homes.
Then of course came 50 years of the Jewish state purchasing or confiscating by force Arab land and putting it into trust for the exclusive use of the Jews. Not the Israelis, but the Jews.
The problem is that having more than a certain number of Arabs living in Palestine would remove "the essential Jewish nature" of Israel, and it would no longer be a nation whose identity was defined by being Jewish which is the point of Zionism.
Admitted, their was no Palestinian nation prior to the formation of Israel. Removing the people who lived there by force was not right however. No matter whether the Europeans did the same to the Jews or not.