There is something called "Settler colonialism" aka parasite, It is a distinct type of colonialism that functions through the replacement of indigenous populations with an invasive settler society that, over time, develops a distinctive identity and sovereignty, and that exactly what happened in Palestine in 1948, Jews from all over the world came to Palestine for work and tourism but ended up stealing and occupying lands. The roots of the problem however is a lot order than that.
It started with the British colonialism, When it's power influence increased and expanded in India, Middle East became easy target to control for both the French and the English, Both countries knew well that they can't stay in the Middle Easy and Africa forever so they came up with two ideas. The first one is dividing the regions into weak and small entities ruled by governments that derived from theirs, The second one is creating an entity, That Entity as people and goverment is thoroughly reliant on the European support, and from that point, Bids from all over Europe called to settle the Jews in Palestine, Since Jews suffered from racism and were oppressed in Europe, It was encouraged to discharge them in Palestine. Therefore, the enterprise interest became common. Why not founding a national home for Jews in Palestine and in the same time we can invest and control all countries in the middle east from there?, In these times, The Nationalism was getting promoted after the great thief wars aka "Napoleon Bonaparte", Every country in Europe started to act they are better than others, Specially France, Britannia and Germany. Theodor herzl who was a Jewish journalist sought a national home for the Jews and claimed that Jews is also a national group. Soon after, The Zionist movement happened in 1855 and Theodor herzl presided the first zionist conference in Switzerland and he sought to set the foundation stone to make home for the Jews in Palestine.
Meanwhile, Palestine at that time was already a country under the Ottomans rule and there was some movements to resist it, but WW1 started. In 1916 Britannia and France agreed to divide the Levant Region (Sykes-picot agreement). In 1917, Britannia issued a public statement "The Balfour declaration" which basically a promise that Britannia would support the jews to have their own national home in Palestine, She started executing the plan and declared the mandate on Palestine in 1920 and appointed Herbert samuel as it's ruler in Palestine, Short after, They made huge discounts for the Jews to facilitate their transportation from their original countries to the new promised land, Palestine. The immigration of Jews began to increase drastically, The first patch had 25k immigrant Jews ( 1882 to 1902 ), The second patch had 35k immigrant Jews (1903 - 1914), The third patch held another 35k ( 1915 - 1923 ), Fourth patch held 67k ( 1924 - 1924 ) and so on.
The Palestinians didn't have any power to stop it but they didn't watch either, In 1891, People who lived in Jerusalem signed a petition to the Ottoman empire to stop the Jewish immigration and prohibit the ownership of properties to the expatriate Jews but nothing changed. After Balfour declaration, Things got worse, Jews now are given lands with little to no money and they were killing Palestinians too and force them out of their lands, The resistance of Palestinians increased, Their first protest was called "Prophet Mossa" ( Moses), in 1920, The second protest was called ( Al-Boraq) in 1929. Things were getting worse and worse and Britannia are ignoring them. An Egyptian scholar called (Az-Al Den- Al Qsam) started to arm the people and gathered lots of fighters from different Arab regions to help in resisting the British government which lead to the biggest Palestinian protest in 1936. Britannia faced this protests with sheer violence after 3 years, since world war II was starting and it needed to silence any protests, They killed 5k Palestinians and injured about 15k more. The percentage of the Jewish people that didn't exceed 3% in 1883, Jumped to 31% in 1946.
In 1947, Britannia removed it's mandate, The united nations recommended to divide the country into two, One speaks Arabic and One speak Hebrew, While Jersulem being under international control, The Palestinians refused because they gave the Jews 58% of their land in times where the Jewish percentage was 31%, It was unfair to them.