There is a widespread but false belief that Mahmoud Abbas is finally prepared to accept the two-state solution proposed by the U.N. in November 1947 when it divided mandatory Palestine into two areas: one for the Jewish People; the other for the Arab People. The Jews of Palestine accepted the compromise division and declared a nation state for the Jewish people to be called by its historic name: Israel. The Arabs of Palestine, on the other hand, rejected the division and declared that they would never accept a state for the Jewish people and statehood for the Palestinian people. They wanted for there not to be a state for the Jewish people more than for there to be a state for their own people. Accordingly, they joined the surrounding Arab armies in trying to destroy Israel and drive its Jewish residents into the sea. They failed back then, but over the years, and to the current day, they continue to want no state for the Jewish people more than they want a state for Palestinian Arabs. That is why Abbas refuses to say that he would ever accept the U.N. principle of two states for two peoples. I know, because I have personally asked him on several occasions.
The short answer… Becuz Islam. This is an Israel-Islam conflict nothing more, nothing less. Islam dictates that Muslims continue efforts to murder Jews at every opportunity until Israel is wiped off the map.