The "reasons" given for Israel's installment in Palestine are entirely inadequate. That the United Nations, Britain or France "gave" Palestine for a Jewish homeland is inadequate: it was not theirs to give. (Moreover, UN "approval" was obtained under duress: UN member countries were threatened with loss of trade or aid if they didn't vote for the partition, which conferred on Jews 54% of Palestine's land though they owned only 7%. Read the details at http://www.al-bushra.org/America/ch9.html.)
That ancient ancestors had that land is inadequate: there had been centuries of discontinuation in possession by Jews, except of a scant portion. That the Old Testament decreed it is inadequate: the Old Testament is not the universal book of man. (In any case the Bible was "doctored" in the 20th century to strengthen the position of Israel. Read more at http://www.historicist.com/articles2/zionscofield2.htm.)
That the Jews were victimized during World War II is inadequate: one victimization doesn't justify another. And that they had no home of their own is inadequate: other people should not be dispossessed of their homes in order to provide them one.