the arab population in the Palestinian mandate were not indigenous. Arabs spread across the Middle East in the 7th century CE, during the rise of Islam. Arab armies led by Muslim forces conquered much of the Middle East.

As Jews migrated to the region, they didn't displace anyone. In fact, one Arab leader in the early20th century said that the region would become more prosperous. Jews who moved there drained swamps eliminating malaria. Jews actually BOUGHT the land from wealthy absentee landlords in Egypt and Turkey.

Judaism as a religion clearly originated in that region whereas Islam originated in Saudi Arabia.