"Palestine has been colonised by Israel for 75 years"
Not quite correct.
Nearly 80% of the historic land of Palestine and the Jewish National Home, as defined by the League of Nations, was severed by the British in 1921 and allocated to Transjordan.
Jewish settlement there was barred.
The UN partitioned the remaining 20-odd percent of Palestine into two states. With Transjordan’s annexation of the West Bank in 1950 and Egypt's occupation of Gaza, Arabs controlled more than 80% of the Mandate territory, while the Jewish State held a mere 17.5%.
The Peel Commission in 1937 concluded that the only logical solution to resolving the contradictory aspirations of the Jews and Arabs was to partition Palestine into separate Jewish and Arab states.
The Jews would have received only 15% of eastern Palestine between the Jordan River and the Mediterranean. A small area, including Jerusalem, was to remain under British control, but 80% of the land was to be united with Transjordan and become independent.
The Arabs rejected the plan because it forced them to accept the creation of a Jewish state and required some Palestinian Arabs to live under “Jewish domination.”
Muslim religious leaders said supporters of the plan were heretics, while the political machine, controlled by the Grand Mufti of Jerusalem, labelled them traitors.
The Zionists opposed the Peel Plan’s boundaries because they would have been confined to 1,900 out of the 10,310 square miles remaining in Palestine. Nevertheless, the Zionists decided to negotiate with the British, while the Arabs refused to consider any compromises.
In 1939, the British White Paper called for establishing an Arab state in Palestine within ten years and limiting Jewish immigration to no more than 75,000 over the following five years. Afterward, no one would be allowed in without the consent of the Arab population. Though the Arabs had been granted a concession on Jewish immigration and been offered independence—the goal of Arab nationalists—they repudiated the White Paper.
With partition, the Palestinians were given a state and the opportunity for self-determination. This, too, was rejected.