"The two districts of Mersina and Alexandretta and portions of Syria lying to the west of the districts of Damascus, Homs, Hama and Aleppo cannot be said to be purely Arab, and should be excluded from the limits demanded." www.jewishvirtuallibrary.org/the-hussein-...
Apart from that, the Balfour declaration dates from 1917. Way before the Shoah. The area was then administered by the British. There was neither a country called Palestine nor was there one named Israel. The UN then gave both their own country. Arabs rejected and lost.
The area was called Palestine! Ever since the ancient Greeks gave it that name. It was inhabited mostly by Arabs, Muslim and Christian, but also Jews and some Christians. They lived PEACEFULLY together! Even Jews themselves state that! You can be stubborn, but you're still wrong.
So, you only pick out of the McMahon- Hossein treaty ehat's not included, but you also aknowlegde that this was before the Balfour declaration. So the Palestines were cheated. And the West, primarily responsible for persecution of Jews/antisemitism, just saw a way to get rid of the Jews...